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THE 


PHYSICAL  BASIS  OF  MIND. 

Mill;  lllustralioits. 


3/ff 


BEIiXG    THE  SECOjVD   SERIES 


PEOBLEMS  OF  LIFE  AND  M 


GEOEGE    HENEY    LEWES. 


BOSTON  AND   NEW  YORK : 

HOUGHTON,  MIFFLIN  AND  COMPANY. 

€f)C  JaibCDJiOe  tOrc^i,  Cambrilrjje. 

ISOL 


AUTHOR'S  EDITION. 


From  Advance  Sheets. 


The  Riverside  Press,  Cambridge,  Mass.,  U.  S.  A. 
Printed  by  H.  O.  Houghton  &  Company. 


3 

PREFACE 


The  title  indicates  that  this  volume  is  restricted  to  the 
group  of  material  conditions  which  constitute  the  organ- 
ism in  relation  to  the  physical  world  —  a  group  which 
furnishes  the  data  for  one  half  of  the  psychologist's 
quest;  the  other  half  being  furnished  by  historical  and 
social  conditions. 

The-  Human  Mind,  so  far  as  it  is  accessible  to  scientific 
inquiry,  has  a  twofold  root,  man  being  not  only  an  animal 
organism  but  an  unit  in  the  social  organism ;  and  hence 
the  complete  theory  of  its  functions  and  faculties  must 
be  sought  in  this  twofold  direction.  This  conception 
( which  has  been  declared  "  to  amount  to  a  revolution  in 
Psychology " ),  although  slowly  prepared  by  the  growing 
conviction  that  Man  could  not  be  isolated  from  Humanity, 
was  first  expounded  in  the  opening  volume  of  these 
Problems  of  Life  and  Mind;  at  least,  I  am  not  aware 
that  any  predecessor  had  seen  lioia  the  specially  human 
faculties  of  Intellect  and  Conscience  were  products  of 
social  factors  co-operatihg  with  the  animal  factors. 

In  considering  the  Physical  Basis  a  large  place  must 
be  assigned  to  the  mechanical  and  chemical  relations 
which  are'  involved  in  organic  functions ;  yet  we  have  to 
recognize  that  this  procedure  of  Analysis  is  artificial  and 
preparatory,  that  none  of  its  results  are  final,  none  rep- 
resent the  synthetic  reality  of  vital  facts.  Hence  one 
leading  object  of  the  following  pages  has  been  every- 
where to  substitute  the  biological  point  of  view  for  the 


VI  PREFACE. 

metaphysical  and  mechanical  points  of  view  which  too 
often  obstruct  research  —  the  one  finding  its  expression 
in  spiritualist  theories,  the  other  in  materialist  theories ; 
both  disregarding  the  plain  principle  that  the  first  req- 
uisite in  a  theory  of  biological  phenomena  must  be  to 
view  them  in  the  light  of  biological  conditions :  in  other 
words,  to  fix  our  gaze  upon  what  passes  in  the  organism, 
and  not  on  what  may  pass  in  the  laboratory,  where  the 
conditions  are  different.  Analysis  is  a  potent  instrument, 
but  is  too  often  relied  on  in  forgetfulness  of  what  consti- 
tutes its  real  aid,  and  thus  leads  to  a  disregard  of  all 
those  conditions  which  it  has  artificially  set  aside.  We 
see  this  in  the  tendency  of  anatomists  and  physiologists 
to  assign  to  one  element,  in  a  complex  cluster  of  co- 
operants,  the  significance  whicli  properly  belongs  to  that 
cluster  :  as  when  the  property  of  a  tissue  is  placed  exclu- 
sively in  a  single  element  of  that  tissue,  the  function 
of  an  organ  assigned  to  its  chief  tissue,  and  a  function  of 
the  organism  to  a  single  organ. 

Another  object  has  been  to  furnish  the  reader  unin- 
structed  in  physiology  with  such  a  general  outline  of  the 
structure  and  functions  of  the  organism,  and  such  details 
respecting  the  sentient  mechanism,  as  may  awaken  an 
interest  in  the  study,  and  enable  him  to  understand  the 
application  of  Physiology  to  Psychology.  If  he  comes 
upon  details  whicli  can  only  interest  specially  educated 
students,  or  perhaps  only  by  them  be  really  understood, 
he  can  pass  over  these  details,  for  their  omission  will  not 
seriously  affect  tlie  bearing  of  the  general  principles.  I 
have  given  the  best  I  had  to  give ;  and  must  leave  each 
reader  to  find  in  it  whatever  may  interest  him.  The  uses 
of  books  are  first  to  stimulate  inquiry  by  awakening  an 
interest ;  secondly,  to  clarify  and  classify  the  knowledge 
already  gained  from  direct  contemplation  of  the  phe- 
nomena.    They  are  stimuli  and  aids  to  observation  and 


PREFACE,  Vll 

thought.  They  should  never  be  allowed  to  see  for  us, 
nor  to  think  for  us. 

The  volume  contains  four  essays.  The  first,  on  the 
NatiLre  of  Life,  deals  with  the  speciality  of  organic  phe- 
nomena, as  distinguished  from  the  inorganic.  It  sets  forth 
the  physiological  principles  which  Psychology  must  in- 
cessantly invoke.  In  the  course  of  the  exposition  I  have 
incorporated  several  passages  from  four  articles  on  Mr. 
Darwin's  hypotheses,  contributed  to  the  Fortnightly  Re- 
view during  the  year  1868.  I  have  also  suggested  a 
modification  of  the  hypothesis  of  Natural  Selection,  by 
extending  to  the  tissues  and  organs  that  principle  of  com- 
petition which  Mr.  Darwin  has  so  luminously  applied  to 
organisms.  Should  this  generalization  of  the  "struggle 
for  existence"  be  accepted,  it  will  answer  many  of  the 
hitherto  unanswerable  objections. 

The  second  essay  is  on  the  Nervous  Mechanism,  setting 
forth  what  is  known  and  what  is  inferred  respecting  the 
structure  and  properties  of  that  all-important  system. 
If  the  sceptical  and  revolutionary  attitude,  in  presence  of 
opinions  currently  held  to  be  established  truths,  surprises 
or  pains  the  reader  unprepared  for  such  doubts,  I  can  only 
ask  him  to  submit  my  statements  to  a  similar  scepticism, 
and  confront  them  with  the  ascertained  evidence.  After 
many  years  of  laborious  investigation  and  meditation,  tlie 
conclusion  has  slowly  forced  itself  upon  me,  that  on  this 
subject  there  is  a  "false  persuasion  of  knowledge"  very 
fatal  in  its  influence,  because  unhesitatingly  adopted  as 
the  ground  of  speculation  both  in  Pathology  and  Psychol- 
ogy. This  persuasion  is  sustained  because  few  are  aware 
how  mucli  of  what  passes  for  observation  is  in  reality 
sheer  hypothesis.  I  have  had  to  point  out  the  great 
extent  to  which  Imaginary  Anatomy  has  been  unsuspect- 
ingly accepted  ;  and  hope  to  liave  done  something  towards 
raising  a  rational  misgiving  in  the  student's  mind  respect- 


Vm  PREFACE. 

ing  "the  superstition  of  the  nerve-cell"  —  a  superstition 
\vhicli  I  freely  confess  to  have  shared  in  for  many  years. 

The  third  essay  treats  of  Animal  Automatism.  Here 
the  constant  insistance  on  the  biological  point  of  view, 
while  it  causes  a  rejection  of  the  mechanical  theory,  ad- 
mits the  fullest  recognition  of  all  the  mechanical  relations 
involved  in  animal  movements,  and  tlms  endeavors  to  rec- 
oncile the  contending  schools.  In  this  essay  I  have  also 
attempted  a  psychological  solution  of  that  much-debated 
question  —  the  relation  between  Body  and  Mind.  This 
solution  explains  why  physical  and  mental  phenomena 
must  necessarily  present  to  our  apprehension  such  pro- 
foundly diverse  characters ;  and  shows  that  JMaterialism, 
in  attempting  to  deduce  the  mental  from  the  physical, 
puts  into  the  conclusion  what  the  very  terms  have  ex- 
cluded from  the  premises ;  whereas,  on  the  liypothesis  of  a 
physical  process  being  only  the  objective  aspect  of  a  mental 
process,  the  attempt  to  interpret  the  one  by  the  other  is 
as  legitimate  as  the  solution  of  a  geometrical  problem  by 
algebra. 

In  the  final  essay  the  Ecjlcx  Theory  is  discussed  ;  and 
here  once  more  the  biological  point  of  view  rectifies  the 
error  of  an  analysis  which  has  led  to  the  denial  of  Sensi- 
bility in  reflex  actions,  because  that  analysis  has  over- 
looked the  necessary  presence  of  the  conditions  which 
determine  Sensibility.  In  these  chapters  are  reproduced 
several  passages  from  the  Physiology  of  Common  Life. 

Accordino-  to  my  orioinal  intention,  this  volume  was  to 
have  included  an  exposition  of  the  part  I  conceive  the 
brain  to  play  in  physiological  and  psychological  processes, 
but  that  must  be  postponed  until  it  can  be  accompanied 
by  a  survey  of  psychological  processes  which  would  ren- 
der the  exposition  more  intelligible. 

The  rKiouv,  March,  1877. 


CONTENTS. 


PROBLE]M  I.    THE  NATURE  OF  LIFE. 
CHAPTER   I. 

PAGE 

The  Problem;  stated '^ 

(The  Position  of  Biology) 4 

{Organisms)      ....•••••  ° 

{Vital  Force) 1* 

{Vital  Force  controlling  Physical  and  Chemical  Forces)       .  16 

CHAPTER    11. 
Definitions  of  Life •        .24; 

CHAPTER    IIL 

Organism,  Organization,  and  Organic  Substance     .        .  37 

{Organism  and  Medium)         ......  45 

{The  Hypothesis  of  Germinal  Matter)          ....  57 

{Organisms  and  Machines)      ......  67 

CHAPTER   IV. 

TuE  Properties  and  Functions 70 

{Does  the  Function  determine  the  Organ  ?)       ■         .         .  78 

CHAPTER    V. 

Evolution 89 

{Natural  Selection  and  Organic  Affinity)         .         .         .  115 
{Mecajntulation)        .         .         .         .         .         .         .         .152 


CONTENTS. 


PROBLEM  II.    THE  NERVOUS  MECILVNISM. 

CHAPTER   I. 

Survey  of  the  System 157 

{The  Early  Forms  of  Ncrve-Centres)        ....  168 

{The  Peripheral  Si/stem)    .......  171 

{Ganglia  and  Centres) 172 

CHAPTER    II. 

Tue  Functional  Relations  of  the  Nervous  System         .  T^G 

CHAPTER    III. 

Neurility 189 

{Origin  of  Nerve-Force 201 

{The  Hypothesis  of  Specific  Energies)          ....  207 

CHAPTER    IV. 

Sensibility 211 

CHAPTER   V. 

Action  without  Nerve-Centres 227 

CHAPTER   VI. 

What  is  taught  by  Embryology? 237 

CHAPTER    VII. 

The  Elementary  Structure  of  the  Nervous  System      .  251 

{Difficulties  of  the  Investigation)     .....  252 

{The  Nerve-Cell) 258 

{The  Nerves) 270 

{The  Neuroglia) 273 

{The  Relations  of  the  Organites) 278 

{Recapitulation) 299 


CONTENTS. 


XI 


CHAPTER    VIII. 

TuE  Laws  of  Nervous  Activity 
(The  Energy  of  Neurility) 
(The  Propagation  of  Excitation) 
(Stimuli)       ...... 

(Stimulation)    ..... 

(The  Late  of  Discharge) 

(The  Law  of  Arrest) 

(The  Hypothesis  of  Inhibitory  Centres)    . 

(Anatomical  Interpretation  of  the  Laws) 


310 
311 
314 
321 
324 
32G 
333 
33G 
339 


PROBLEM  in.    ANIMAL  AUTOJ^IATISM. 

CHAPTER   L 
The  Course  of  Modern  Thought       .... 


345 


CHAPTER    IL 


The  Vital  Mechanish 


363 


CHAPTER   IIL 

The  Relation  of  Body  and  Mind 


376 


CHAPTER   IV. 

Consciousness  and  Unconsciousness  . 


399 


CHAPTER   V. 
Voluntary  and  Involuntary  Actions 


415 


CHAPTER   VL 
The  Problem  stated 431 


CHAPTER    VIL 
Is  Feeling  an  Agent? 


440 


xn  CONTENTS. 

PROBLEM  IV.    THE  REFLEX  THEORY. 

CHAPTER    L 
The  Problem  stated 467 

CHAPTER   IL 
Deductions  from  General  Laws 490 

CHAPTER   IIL 

Inductions  from  Particular  Observations        .        .        .  509 

{Cerebral  Reflexes)         . 511 

{Discrimination)        . 520 

{.Memory)      .         .  ' 522 

'{Instinct) 522 

{The  Mechanism  of  Instinct)  .         .         .         .         .         .  536 

{Acqriisition)     .         .         . 546 

CHAPTER    IV. 
Negative  Inductions 550 


PROBLEM    I, 


THE  NATURE  OF  LIFE. 

"La  Physiologie  a  pour  but  d'exposer  les  phenomenes  de  la  vie  luimaine  et 
les  conditions  d'oii  ils  dependent.  Pour  y  arriver  d'une  maniere  sure,  11  faut 
necessairement  avant  tout  determiner  quels  sont  les  phenomenes  qu'on  designe 
sous  le  nom  de  vie  en  general.  C'est  pourquoi  la  premiere  chose  a  faire  est 
d'etudier  les  proprietes  geuerales  du  corps  qu'on  appelle  organiques  ou  vi- 
vans."  — TiEDEMANN,  Traite  de  Physiologie  de  V Homme,  I.  2. 

"Some  weak  and  inexperienced  persons  vainly  seek  by  dialectics  and  far- 
fetched, arguments  either  to  upset  or  establish  things  that  are  only  to  be 
founded  on  anatomical  demonstration  and  believed  on  the  evidence  of  the 
senses.  He  who  truly  desires  to  be  informed  of  the  question  in  hand  must  be 
lield  bound  either  to  look  for  himself,  or  to  take  on  trust  the  conclusions  to 
which  they  who  have  looked  have  come."  —  Harvey,  Second  Dissertation 
to  Riolan. 


THE  NATURE  OF  LIFE. 


CHAPTER    I. 

THE   PROBLEM   STATED. 

1.  Although  for  convenience  we  use  the  terms  Life 
and  Mind  as  representing  distinct  orders  of  phenomena, 
the  one  objective  and  the  other  subjective,  and  although 
for  centuries  they  have  designated  distinct  entities,  or 
forces  having  different  substrata,  we  may  now  consider  it 
sufficiently  acknowledged  among  scientific  thinkers  that 
every  problem  of  Mind  is  necessarily  a  problem  of  Life, 
referring  to  one  special  group  of  vital  activities.  It  is 
enough  that  Mind  is  never  manifested  except  in  a  living 
organism  to  make  us  seek  in  an  analysis  of  organic  phe- 
nomena for  the  material  conditions  of  every  mental  fact. 
Mental  phenomena  when  observed  in  others,  although 
interpretable  by  our  consciousness  of  what  is  passing  in 
ourselves,  can  only  be  objective  phenomena  of  the  vital 
organism, 

2.  On  this  ground,  if  on  this  alone,  an  acquaintance 
with  the  general  principles  of  structure  and  function  is 
indispensable  to  the  psychologist ;  although  only  of  late 
years  has  this  been  fully  recognized,  so  that  men  pro- 
foundly ignorant  of  tlie  organism  have  had  no  hesitation 
in  theorizing  on  its  highest  functions.  In  sayinjr  that  such 
knowledge  is  indispensable,  I  do  not  mean  that  in  the 
absence  of  such  knowledge  a  man  is  debarred  from  under- 
standing much  of  the  results  reached  by  investigators. 


4  THE   niYSICAL   BASIS   OF   MIXD. 

nor  that  he  may  not  himself  make  useful  observations 
and  classiiieations  of  iJsychological  facts.  It  is  possible 
to  read  books  on  Natural  History  with  intelligence  and 
profit,  and  even  to  make  good  observations,  without  a 
scientific  groundwork  of  biological  instruction  ;  and  it  is 
possible  to  arrive  at  empirical  facts  of  hygiene  and  medi- 
cal treatment  without  any  physiological  instruction.  But 
in  all  three  cases  the  absence  of  a  scientific  basis  will  ren- 
der the  knowledge  fragmentary  and  incomplete  ;  and  this 
ought  to  deter  every  one  from  offering  an  opinion  on  de- 
batable questions  which  pass  beyond  the  limit  of  subjec- 
tive observations.  The  psychologist  who  has  not  prepared 
himseK  by  a  study  of  the  organism  has  no  more  right  to 
be  heard  on  the  genesis  of  the  psychical  states,  or  of  the 
relations  between  body  and  mind,  than  one  of  the  laity 
has  a  right  to  be  heard  on  a  question  of  medical  treat- 
ment. 

THE   rOSITIOX   OF   BIOLOGY. 

3.  Science  is  the  systematic  classification  of  Experi- 
ence. It  postulates  unity  of  Existence  with  great  varieties 
in  the  Modes  of  Existence ;  assuming  that  there  is  one 
Matter  everywhere  the  same,  under  great  diversities  in 
the  complications  of  its  elements.  The  distinction  of 
Modes  is  not  less  indispensable  than  the  identification  of 
the  elements.  These  Modes  range  themselves  under  three 
supreme  heads  :  Force,  Life,  ]\lind.  Under  the  first,  range 
the  general  properties  exhibited  by  cdl  substances ;  under 
the  second,  the  general  properties  exhibited  by  organized 
substances ;  under  the  third,  the  general  properties  ex- 
hibited by  organized  animal  substances.  The  first  class 
is  subdivided  into  Physics,  celestial  and  terrestrial,  and 
Chemistry.  Physics  treats  of  substances  which  move  as 
masses,  or  which  vibrate  and  rotate  as  molecules,  without 
undergoing  any  appreciable  change  of  structural  integrity ; 


THE   NATURE   OF  LIFE.  5 

they  show  changes  of  position  and  state,  without  corre- 
sponding changes  in  their  elements.  Chemistry  treats  of 
substances  which  undergo  molecular  changes  of  composi- 
tion  destructive  of  their  integrity.  Thus  the  blow  which 
simply  moves  one  body,  or  makes  it  vibrate,  explodes 
another.  The  friction  which  alters  the  temperature  and 
electrical  state  of  a  bit  of  glass,  ignites  a  bit  of  phos- 
phorus, and  so  destroys  its  integrity  of  structure,  convert- 
ing phosphorus  into  phosphoric  acid. 

4.  The  second  class,  while  exhibiting  both  physical 
and  chemical  properties,  is  markedly  distinguished  by  the 
addition  of  properties  called  vital.  Their  peculiarity  con- 
sists in  this  :  they  undergo  molecular  changes  of  compo- 
sition and  decomposition  which  are  simultaneous,  and  hy 
this  simultaneity  preserve  their  integrity  of  structure.  They 
change  their  state,  and  their  elements,  yet  preserve  their 
unity,  and  even  when  differentiating  continue  specific. 
Unlike  all  other  bodies,  the  organized  are  born,  grow,  de- 
velop, and  decay,  through  a  prescribed  series  of  graduated 
evolutions,  each  stage  being  the  indispensable  condition 
of  its  successor,  no  stage  ever  appearing  except  in  its 
serial  order. 

5,  The  third  class,  while  exhibiting  all  the  character- 
istics of  tlie  two  preceding  classes,  is  specialized  by  the 
addition  of  a  totally  new  property,  called  Sensibility, 
which  subjectively  is  Feeling.  Here  organized  substance 
has  become  animal  substance,  and  Vegetality  has  been 
developed  into  Animality  by  the  addition  of  new  factors, 
—  new  complexities  of  the  elementary  forces.  Many,  if 
not  most,  philosophers  postulate  an  entirely  new  Exist- 
ence, and  not  simply  a  new  Mode,  to  account  lor  the 
manifestations  of  Mind ;  they  refuse  to  acknowledge  it 
to  Ijo  a  vital  manifestation,  they  demand  that  to  Life  be 
added  a  separate  substratum,  the  Soul.  Tliis  is  not  a 
point  to  be  discussed  here.     We  may  be  content  with  the 


6  THE   niYSICAL   BASIS    OF   MIND. 

assertion  that  liowever  great  the  phenomenal  difference 
between  lliunanity  and  Aniraality  (a  difference  we  shall 
hereafter  see  to  be  the  expression  of  a  new  factor,  namely, 
the  social  factor),  nevertheless  the  distinctive  attribute  of 
Sensibility,  out  of  which  rise  Emotion  and  Cognition, 
marks  the  inseparable  kinship  of  mental  wdth  vital  jihe- 
nomena. 

Thus  all  the  various  Modes  of  Existence  may,  at  least 
in  their  objective  aspect,  be  ranged  under  the  two  divis- 
ions of  Inorganic  and  Organic,  —  Non-living  and  Living, 
—  and  these  are  respectively  the  objects  of  the  cosmologi- 
cal  and  the  biological  sciences. 

6.  The  various  sciences  in  their  serial  development 
develop  the  wliole  art  of  Method.  Mathematics  devel- 
ops abstraction,  deduction,  and  definition ;  Astronomy 
abstraction,  deduction,  and  observation  ;  Physics  adds  ex- 
periment ;  Chemistry  adds  nomenclature ;  Biology  adds 
classification,  and  for  the  first  time  brings  into  promi- 
nence the  important  notion  of  conditions  of  existence,  and 
the  variation  of  phenomena  under  varying  conditions  :  so 
that  the  relation  of  the  organism  to  its  medium  is  one 
never  to  be  left  out  of  sight.  In  Biology  also  clearly 
emerges  for  the  first  time  what  I  regard  as  the  true  notion 
of  causality,  namely,  the  procession  of  causes,  —  the  com- 
bination of  factors  in  the  product,  and  not  an  ah  extra  de- 
termination of  the  product.  In  Vitality  and  Sensibility 
we  are  made  aware  that  the  causes  are  in  and  not  outside 
the  organism  ;  that  the  organic  effect  is  the  organic  cause 
in  operation ;  that  there  is  autonomy  but  no  autocracy ; 
the  effect  issues  as  a  resultant  of  the  co-operating  condi- 
tions. In  Sociology,  finally,  w^e  see  brought  into  promi- 
nence the  historical  conditions  of  existence.  From  the  due 
appreciation  of  the  conditions  of  existence,  material  and 
historical,  we  seize  the  true  significance  of  the  principle 
of  Relativity. 


THE   NATURE   OF  LIFE.  ■  7 

7.  Having  thus  indicated  the  series  of  the  abstract 
sciences  we  have  now  to  consider  more  closely  the  char- 
acter of  Biology.  The  term  was  proposed  independently 
yet  simultaneously  in  Germany  and  France,  in  the  year 
1802,  by  Treviranus  and  Lamarck,  to  express  "  the  study 
of  the  forms  and  phenomena  of  Life,  the  conditions  and 
laws  by  which  these  exist,  and  the  causes  which  produce 
them."  Yet  only  of  late  years  has  it  gained  general  ac- 
ceptance in  France  and  England.  The  term  Cosmology, 
for  what  are  usually  called  the  Physical  Sciences,  has  not 
yet  come  into  general  use,  although  its  appropriateness 
must  eventually  secure  its  recognition. 

Biology,  —  the  abstract  science  of  Life, — -embracing, 
the  whole  organic  world,  includes  Vegetality,  Animality, 
and  Humanity ;  the  biological  sciences  are  Phytology, 
Zoology,  and  Anthropology.  Each  of  the  sciences  has  its 
cardinal  divisions,  statical  and  dynamical,  namely.  Mor- 
phology —  the  science  of  form,  —  and  Physiology  —  the 
science  of  function. 

Morphology  embraces  —  1°,  Anatomy,  i.  e.  the  descrip- 
tion of  the  parts  then  and  there  present  in  the  organism  ; 
and  these  parts,  or  organs,  are  further  described  by  the 
enumeration  of  their  constituent  tissues  and  elements  ; 
and  of  these  again  the  proximate  principles,  so  far  as  they 
can  be  isolated  without  chemical  decomposition.  2°,  Or- 
(lanogcny,  i.  e.  the  history  of  the  evolution  of  organs  and 
tissues. 

Pliysiology  embraces  the  properties  and  functions  of 
the  tissues  and  organs  —  the  primary  conditions  of  Growth 
and  Development  out  of  which  rise  the  higher  functions 
bringing  the  organi.sm  into  active  relation  with  the  sur- 
rounding medium.  Tlie  first  group  of  properties  and 
functions  are  called  those  of  vegetal,  or  organic  life  ;  the 
second  those  of  animal,  or  relative  life. 


THE   rilYSICAL   BASIS    OF   MIND. 


OKGANISMS. 

8.  It  will  be  needful  to  fix  M'itli  precision  the  terms, 
Ori^anism,  Life,  Property,  and  Function. 

An  organism,  although  usually  signiiying  a  more  or  less 
complex  unity  of  organs,  because  the  structures  which 
first  attracted  scientific  attention  were  all  thus  markedly 
distinguished  from  inorganic  bodies,  has  by  the  gradual 
extensions  of  -research  been  necessarily  generalized,  till  it 
now  stands  for  any  organized  substance  capable  of  inde- 
pendent vitality :  in  other  words,  any  substance  having 
the  specific  combination  of  elements  which  manifests  the 
serial  phenomena  of  growth,  development,  and  decay. 
There  are  organisms  that  have  no  differentiated  organs. 
Thus  a  microscopic  formless  lump  of  semifluid  jelly-like 
substance  (Protoplasm)  is  called  an  organism,  because  it 
feeds  itself,  and  reproduces  itself.  There  are  advantages 
and  disadvantages  in  such  extensions  of  terms.  These  are 
notable  in  the  parallel  extension  of  the  term  Life,  which 
originally  expressing  only  the  complex  activities  of  com- 
plex organisms,  has  come  to  express  the  simplest  activities 
of  protoplasm.  Thus  a  Monad  is  an  organism  ;  a  Cell  is 
an  organism  ;  a  Plant  is  an  organism  ;  a  Man  is  an  organ- 
ism. And  each  of  these  organisms  is  said  to  have  its  Life, 
because 

"  Through  all  the  mighty  commonwealth  of  things 
Up  from  the  creeping  worm  to  sovereign  man  "  * 

there  is  one  fundamental  group  of  conditions,  one  organized 
substance,  one  vitalit3^ 

Obviously  this  unity  is  an  abstraction.  In  reality,  the 
life  manifested  in  the  Man  is  not  the  life  manifested  in 
the  Monad :  he  has  Functions  and  Faculties  which  the 
Monad  has  no  trace  of;  and  if  the  two  organisms  have 
certain  vital  characteristics  in  common,  this  unity  is  only 

*   WORDSWOKTH. 


THE   NATURE   OF   LIFE.  9 

recognized  in  an  ideal  construction  which  lets  drop  all  con- 
crete differences.  The  Life  is  different  when  the  organism 
is  different.  Hence  any  definition  of  Life  would  be  man- 
ifestly insufficient  which  while  it  expressed  the  activities 
of  the  Monad  left  unexpressed  the  conspicuous  and  im- 
portant activities  of  higher  organisms.  A  sundial  and  a 
repeater  will  each  record  the  successive  positions  of  the 
sun  in  the  heavens ;  but  although  both  are  instruments 
for  marking  time,  the  sundial  will  not  do  the  work  of  the 
repeater  ;  the  complexity  and  delicacy  of  the  watch  mech- 
anism are  necessary  for  its  more  varied  and  delicate  uses. 
A  semifluid  bit  of  protoplasm  will  feed  itself ;  but  it  will 
not  feed  and  sustain  a  complex  animal ;  nor  will  it  feel 
and  think. 

9.  Neglect  of  this  point  has  caused  frequent  confusion 
in  the  attempts  to  give  satisfactory  definitions.  Biologists 
ouglit  to  have  been  warned  by  the  fact  that  some  of  the 
most  widely  accepted  definitions  exclude  the  most  con- 
spicuous phenomena  of  Life,  and  are  only  applicable  to  the 
vegetable  world,  or  to  the  vegetal  processes  in  the  animal 
world.  A  definition,  however  abstract,  should  not  exclude 
essential  characters.  The  general  consent  of  mankind  has 
made  Life  synonymous  with  Mode  of  Existence.  By  the 
life  of  an  animal  is  meant  the  existence  of  that  animal : 
when  dead  the  animal  no  longer  exists ;  the  substances 
of  which  the  organism  was  composed  exist,  but  under 
another  mode  ;  their  connexus  is  altered,  and  the  organ- 
ism vanishes  in  the  alteration.  It  is  a  serious  mistake  to 
call  the  corpse  an  organism ;  for  that  special  combination 
which  constituted  the  organism  is  not  present  in  the  corpse. 
Tliis  misconception  misleads  some  speculative  minds  into 
assigning  life  to  the  universe.  The  universe  assuredly 
exists,  l)ut  it  does  not  live ;  its  existence  can  only  bo 
identified  with  life,  such  as  we  observe  in  organisms,  by 
a  complete  obliteration  of  the  speciality  which  the  term 
1  * 


10  THE   niYSICAL   BASIS   OF   MIND. 

Life  is  meant  to  designate.  Yet  many  have  not  only 
pleased  themselves  with  such  a  conception,  but  have  con- 
ceived the  universe  to  be  an  organism  fashioned,  directed, 
and  sustained  by  a  soul  like  that  of  man  —  the  anima 
mundi.  This  is  to  violate  all  scientific  canons.  The  life 
of  a  plant-organism  is  not  the  same  as  the  life  of  an 
animal-organism  ;  tlie  life  of  an  animal-organism  is  not 
the  same  as  the  life  of  a  human-organism  ;  nor  can  the  life 
of  a  human-organism  be  the  same  as  the  life  of  the  world- 
organism.  The  unity  of  Existences  does  not  obliterate 
the  variety  of  Modes  ;  yet  it  is  the  speciality  of  each  ]\Iode 
Avhicli  Science  investigates ;  to  some  of  these  Modes  the 
term  Life  is  consistently  applied,  to  others  not ;  and  if  we 
merge  them  all  in  a  common  term,  we  must  then  invent 
a  new  term  to  designate  the  Modes  now  included  under 
nfe. 

10.  In  resisting  this  unwarrantable  extension  of  the 
term  I  am  not  only  pointing  to  a  speculative  error,  but 
also  to  a  serious  biological  error  common  in  both  spirit- 
ualist and  materialist  schools,  namely  that  of  assigning 
Life  to  other  than  organic  agencies.  Instead  of  recogniz- 
ing the  speciality  of  this  Mode  of  Existence  as  dependent 
on  a  speciality  of  the  organic  conditions,  the  spiritualist 
assigns  Life  to  some  extra-organic  Vital  Principle,  the 
materialist  assigns  it  to  some  inorganic  agent  —  physical 
or  chemical.  Waiving  for  the  present  all  discussion  of 
Vitalism,  let  us  consider  in  what  sense  we  must  separate 
organic  from  all  inorganic  phenomena. 

11.  There  is  a  distinction  between  inorganic  and  organic 
which  may  fitly  be  called  radical :  it  lies  at  the  root  of 
the  phenomena,  and  must  be  accepted  as  an  ultimate  fact, 
although  the  synthesis  on  which  it  depends  is  analytically 
reducible  to  a  complication  of  more  primitive  conditions. 
It  has  been  already  indicated  in  §  5.  All  organisms  above 
the  very  simplest  are  syntheses  of  three  terms  :  Structure, 


THE   NATURE   OF   LIFE.  H 

Aliment,  and  Instrument.  Crystals,  like  all  other  anor- 
ganisms  have  structure,  and  in  a  certain  sense  they  may 
be  said  to  grow  {Mineralia  crescunt),  though  the  growth 
is  by  increase  and  not  by  modification :  *  the  motherlye, 
which  is  the  food  of  the  crystal,  is  never  brought  to  the 
crystal,  nor  prepared  for  it,  by  any  instrumental  agency 
of  the  crystal.  Organisms  are  exclusively  instrumental ; 
the  organ  is  an  instrument.  The  structural  integrity  of 
an  organism  is  thus  preserved  through  an  alimentation 
which  is  effected  through  special  instruments.  Nothing 
like  this  is  visible  in  anorganisms. 

The  increase  of  a  crystal  is  further  distinguishable  from 
the  growth  of  an  organism,  in  the  fact  of  its  being  simple 
accretion  without  development :  and  the  structure  of  the 
crystal  is  distinguishable  from  that  of  an  organism  in  the 
fact  that  its  integrity  is  preserved  by  the  exclusion  of  all 
molecular  change,  and  not  by  the  simultaneous  changes 
of  molecular  decomposition  and  recomposition.  Inor- 
ganic substances  are  sometimes  as  unstable  as  organic, 
sometimes  even  more  unstable ;  but  their  instability  is 
the  source  of  their  structural  destruction  —  they  change 
into  other  species  ;  whereas  the  instability  of  organized 
substances  {not  of  organic)  is  the  source  of  their  structural 
integrity  :  the  tissue  is  renovated,  and  its  renovation  is  a 
consequence  of  its  waste. 

12.  But  while  the  distinction  is  thus  radical,  when  we 
\iew  the  organism  from  the  real  —  that  is,  from  the  syn- 
thetic point  of  view  —  we  must  also  urge  the  validity  of 

*  Crystals  not  only  grow  by  assimilation,  but  even  repair  injuries, 
with  a  certain  superficial  resemblance  to  the  repair  of  animal  tissues. 
Thu.s,  according  to  tlic  expiM-iments  of  JonD.VN  cited  by  Sir  .Tames  Pagkt 
{Lectures  o-fi  Surgical  ratkoUxjy,  I.  153,  and  2d  ed.  p.  115),  an  octohe- 
dral  crystal  of  alum,  if  fractured  and  replaced  in  a  motherlye  will  in  a 
few  days  exhibit  a  complete  restoration  of  the  original  form.  The  whole 
crystal  increases,  but  the  increase  is  greatest  on  the  broken  edge,  and  the 
octohcdral  form  is  completely  renewed.     (Comji.  §  113.) 


12  THE   PHYSICAL   BASIS   OF  MIND. 

the  analytical  point  of  view,  which  seizes  on  the  con- 
ditions here  coni})licated  in  a  special  group,  and  declares 
these  conditions  to  he  severally  recognizahle  equally  in 
anorganisms  and  in  organisms.  All  the  fundamental 
])ro])erties  of  Matter  are  recognizahle  in  organized  JMatter. 
Tlie  elementary  substances  and  forces  familiar  to  physi- 
cists and  chemists  are  the  materials  of  the  biologist ;  nor 
has  there  been  found  a  single  organic  substance,  however 
special,  that  is  not  reducible  to  inorganic  elements.  We 
see,  then,  that  organized  Matter  is  only  a  special  combina- 
tion of  that  which  in  other  combinations  presents  chemical 
and  physical  phenomena ;  and  we  are  prepared  to  find 
Chemistry  and  Physics  indispensable  aids  in  our  analysis 
of  organic  phenomena.  Aids,  but  only  aids  ;  indispensa- 
ble, but  iusufficient. 

13.  There  is  therefore  an  ambiguity  in  the  common 
statement  that  organized  matter  is  not  ordinary  matter. 
Indisputable  in  one  sense,  this  is  eminently  disputable 
when  it  is  interpreted  as  evidence  of  a  peculiar  Vital  Force 
"wholly  unallied  with  the  primary  energy  of  Motion." 
If  by  "  ordinary  matter  "  be  meant  earths,  crystals,  gases, 
vapors,  then  assuredly  organized  matter  is  not  ordinary. 
"  Between  the  living  state  of  matter  and  its  non-living 
state,"  says  Dr.  Beale,"  there  is  an  absolute  and  irreconcil- 
able difference ;  so  far  from  our  being  able  to  demonstrate 
that  the  non-living  passes  by  gradations  into  or  gradually 
assumes  the  scale  or  condition  of  the  living,  the  transition 
is  sudden  and  abrupt,  and  matter  already  in  the  living 
state  may  pass  into  the  non-living  condition  in  the  same 
sudden  and  complete  manner."  *  The  ambiguity  here  is 
sensible  in  the  parallel  case  of  the  difference  between 
crystallizable  and  coagulable  matter,  or  between  one  crys- 
tal and  another.     If  we  can  decompose  the  organic  into 

*  Cited  by  Dry.sdale,  Life  and  the  Equivalence  of  Force,  Part  II. 
p.  149. 


THE  NATURE   OF   LIFE.  13 

the  inorganic,  this  shows  that  the  elements  of  the  one 
are  elements  of  the  other;  and  if  we  are  not  yet  able 
to  recompose  the  inorganic  elements  into  organic  matter 
(not  at  least  in  its  more  complex  forms),  may  this  not  be 
due  to  the  fact  that  we  are  ignorant  of  the  proximate 
synthesis,  ignorant  of  the  precise  way  in  which  the  ele- 
ments are  combined  ?  I  may  have  every  individual  part 
of  a  machine  before  me,  but  unless  I  know  the  proper 
position  of  each,  I  cannot  with  the  parts  reconstruct  the 
machine.  Indeed  the  very  common  argument  on  which 
so  much  stress  is  laid  in  favor  of  some  mysterious  Prin- 
ciple as  the  source  of  organic  phenomena,  namely,  that 
human  skill  is  hopelessly  baffled  in  the  attempt  to  make 
organic  substances,  still  more  a  living  cell,  is  futile.  Men 
can  make  machines,  it  is  said,  but  not  organisms,  ergo 
organisms  must  have  a  spiritual  origin.  But  the  fact  is 
that  no  man  can  make  a  machine,  unless  he  take  advan- 
tage of  the  immense  traditions  of  our  race,  and  apply  the 
skill  of  millions  who  have  worked  and  thought  before  him, 
slowly  and  tentatively  discovering  the  necessary  means 
of  mechanical  effect.  The  greatest  thinker,  or  the  deepest 
scholar,  who  did  not  place  himself  in  the  line  of  the  tra- 
dition, and  learn  the  principles  of  mechanism,  and  the 
properties  of  the  materials,  would  Ije  as  incapable  of  mak- 
ing a  watch,  as  the  physiologist  now  is  of  making  a  cell. 
But  the  skill  of  man  has  already  succeeded  in  making 
many  organic  substances,  and  will  perhaps  eventually 
succeed  in  making  a  cell,  certainly  will,  if  ever  the  special 
synthesis  which  binds  the  elements  together  should  be 
discovered.  Not  that  such  a  discovery  would  alter  the 
position  of  Biology  in  relation  to  Chemistry.  The  making 
of  albumen,  nay,  the  construction  of  an  organism  in  the 
laboratory,  would  not  in  tlie  least  affect  the  foundation  of 
Biology,  would  not  obliterate  the  radical  difference  be- 
tween organisms  and  anorganisms.     It  is  the  speciality  of 


14  THE   niYSICAL   BASIS    OF   MIND, 

organic  phenomena  wliicli  gives  them  a  special  place, 
although  the  speciality  may  only  be  due  to  a  complication 
of  general  agencies. 

VITAL    FORCE. 

14.  A  similar  ambiguity  to  that  of  the  phrase  "  ordinary 
matter  "  lies  in  the  equally  common  phrase  "  Vital  Force," 
■which  is  used  to  designate  a  special  group  of  agencies, 
and  is  then  made  to  designate  an  agent  which  has  no 
kinship  with  the  general  group  ;  that  is  to  say,  instead  of 
being  employed  in  its  real  signification —  that  which  alone 
represents  our  knowledge  —  as  the  abstract  statical  ex- 
pression of  the  complex  conditions  necessary  to  the  mani- 
festation of  vital  phenomena,  or  as  the  abstract  dynamical 
expression  of  the  phenomena  themselves,  it  is  employed 
as  an  expression  of  tlieir  unknown  Cause,  which,  because 
unknown,  is  dissociated  from  the  known  conditions,  and 
erected  into  a  mysterious  Principle,  having  no  kinship 
with  ]\Iatter.  In  the  first  sense  the  term  is  a  shorthand 
symbol  of  what  is  known  and  inferred.  The  known  con- 
ditions are  the  relations  of  an  organism  and  its  medium, 
the  organism  being  the  union  of  various  substances  all 
of  which  have  tlieir  peculiar  properties  when  isolated ; 
properties  tliat  disappear  in  the  union,  and  are  replaced 
by  others,  which  result  from  the  combination  —  as  the 
properties  of  chlorine  and  sodium  all  disappear  in  the 
sea-salt  which  results  from  their  union ;  or  as  the  proper- 
ties of  oxygen  and  the  properties  of  hydrogen  disappear 
and  are  replaced  by  the  pro]3erties  of  water.  When  there- 
fore Vital  Force  is  said  to  be  exalted  or  depressed,  the 
phrase  has  rational  interpretation  in  tlie  alteration  which 
has  taken  place  in  one  or  more  of  the  conditions,  internal 
and  external :  a  change  in  the  tissues,  the  plasma,  or  the 
environment,  exalts  or  depresses  the  energy  of  the  vital 
manifestations ;    and    to    suppose   that   this   is   effected 


THE   NATUKE   OF  LIFE.  15 

through  the  agency  of  some  extra-organic  Principle  is  a 
purely  gratuitous  fiction. 

15.  That  we  ai'e  ignorant  of  one  or  more  of  the  indis- 
pensable conditions  symbolized  in  the  abstract  term  Vi- 
tality or  Vital  Force,  is  no  reason  for  quitting  the  secure 
though  difficult  path  of  Observation,  and  rushing  into 
the  facile  but  delusive  path  of  Fiction,  which  proposes 
metempirical  Agents  (in  the  shape  of  Vital  and  Psychical 
Principles)  to  solve  the  problems  of  Life  and  Mind.  We 
may  employ  the  term  Vital  Force  to  label  our  observa- 
tions, togetlier  with  all  that  still  remains  unobserved ; 
and  we  are  bound  to  recognize  the  line  which  separates 
observation  from  inference,  what  is  proved  from  what  is 
inferred ;  but  while  marking  the  limits  of  the  known, 
we  are  not  to  displace  the  known  in  favor  of  the  un- 
known. It  is  said  that  because  of  our  ignorance  we  must 
assume  these  causes  of  Life  and  Mind  to  be  unallied  with 
known  material  causes,  and  belonging  to  a  different  order 
of  existences.  This  is  to  convert  ignorance  into  a  proof ; 
and  not  only  so,  but  to  allow  what  we  do  not  know  to  dis- 
place what  we  do  know.  The  organicist  is  ready  to  admit 
that  much  has  still  to  be  discovered  ;  the  vitalist,  taking 
his  stand  upon  this  unknown,  denies  that  what  lias  been 
discovered  is  really  important,  and  declares  that  the  real 
agent  is  wholly  unallied  to  it.     How  can  he  know  this  ? 

He  does  not  know  it ;  he  assumes  it ;  and  the  chief 
evidence  he  adduces  is  that  the  ordinary  laws  of  inorganic 
matter  are  incapable  of  explaining  tlie  plienomcna  of  or- 
ganized matter;  and  that  pliysicaland  clienucal  forces  are 
controlled  l)y  vital  force.  I  accept  botli  these  positions, 
stripping  tlicm,  however,  of  tlieir  ainl)iguities.  The  laws 
of  ordinary  matter  are  clearly  incompetent  in  tlie  case  of 
matter  which  is  not  ordinary,  but  specialized  in  organisms  ; 
and  when  we  come  to  treat  of  Materialism  we  sliall  see 
how  unscientific  have  been  the  hypotheses  which  disre- 


IC  THE   niYSICAL   BASIS   OF   MIND. 

gard  the  distinction.     The  question  of  control  is  too  inter- 
esting and  important  to  be  passed  over  here. 

VITAL  FOHCE  CONTROLLING  PHYSICAL  AND  CHEMICAL  FOKCES. 

16.  The  facts  relied  on  by  the  vitalists  are  facts  which 
every  organicist  will  emphasize,  though  he  will  interpret 
them  difiereutly.  When,  for  example,  it  is  said  that 
"  Life  resists  the  effect  of  mechanical  friction,"  and  the 
proof  adduced  is  the  fact  that  the  friction  which  will  thin 
and  M-ear  away  a  dead  body  is  actually  the  cause  of  the 
thickening  of  a  living  —  the  skin  of  a  laborer's  hand  being 
thickened  by  his  labor ;  the  explanation  is  not  that  Life, 
an  extra-organic  agent,  "  resists  mechanical  friction  "  — 
for  the  mechanical  effect  is  not  resisted  (the  skin  is  rubbed 
off  the  rower's  hand  sooner  than  the  w^ood  is  rubbed  off 
the  oar)  —  but  that  Life,  i.  e.  organic  activity  repairs  the 
waste  of  tissue. 

17.  Again,  although  many  of  the  physical  and  chemical 
processes  which  invariably  take  place  under  the  influences 
to  which  the  substances  are  subjected  out  of  the  organism, 
will  not  take  place  at  all,  or  will  take  place  in  different 
degrees,  when  the  substances  are  in  the  organism,  this  is 
important  as  an  argument  against  the  notion  of  vital 
phenomena  being  deducible  from  physical  and  chemical 
lav)s,  but  is  valueless  as  evidence  in  favor  of  an  extra- 
organic  agent.  Let  us  glance  at  one  or  two  striking  ex- 
amples. 

18.  Xo  experimental  inquirer  can  have  failed  to  observe 
the  often  contradictory  results  which  seemingly  unimpor- 
tant variations  in  the  conditions  bring  about ;  no  one  can 
have  failed  to  observe  what  are  called  chemical  affinities 
wholly  frustrated  by  vital  conditions.  Even  the  ordinary 
laws  of  Diffusion  are  not  always  followed  in  the  organism. 
The  Amceba,  though  semifluid,  resists  diffusion  when  alive  ; 
but  when  it  dies  it  swells  and  bursts  by  osmosis.     The 


THE  NATURE   OF   LIFE.  17 

exchange  of  gases  does  not  take  place  in  the  tissues,  pre- 
cisely as  in  our  retorts.  The  living  muscle  respires,  that 
is,  takes  up  oxygen  and  gives  out  carbonic  acid,  not  on 
the  principle  of  simple  diffusion,  but  by  two  separable 
])hysiological  processes.  The  carbonic  acid  is  given  out, 
even  when  there  is  no  oxygen  whatever  present  in  the 
atmosphere,  and  its  place  may  then  be  supplied  by  hydro- 
gen; and  this  physiological  process  is  so  different  from 
the  physical  proqess  which  goes  on  in  the  dead  muscle 
(the  result  of  putrefaction),  that  it  has  been  proved  by 
Pianke  to  go  on  when  the  temperature  is  so  low  that  all 
putrefaction  is  arrested.  The  same  experimenter  finds  * 
that  whereas  living  nerve  will  take  up,  by  imbibition,  10 
per  cent  of  potash  salts,  it  will  not  take  up  1  per  cent  of 
soda  salts,  presented  in  equal  concentration  ;  and  he  points 
to  the  general  fact  that  the  absorption  of  inorganic  sub- 
stances does  not  take  place  according  to  the  simple  laws 
of  diffusion,  but  tliat  living  tissues  have  special  laws,  the 
nerve,  for  instance,  having  a  greater  affinity  for  neutral 
potash  salts  than  for  neutral  soda  salts.  Let  me  add,  by 
way  of  anticipating  the  probable  argument  that  may  urge 
this  in  favor  of  Vital  Principle  which  is  lightly  credited 
with  the  prescience  of  final  causes,  that  so  far  from  this 
"  elective  affinity "  of  the  tissues  being  intelligent  and 
always  favorable,  Eanke's  experiments  unequivocally  show 
that  it  is  more  active  towards  destructive,  poisonous  sub- 
stances, than  towards  the  reparative,  alimentary  substances ; 
which  is  indeed  consistent  with  the  familiar  experience 
that  poisons  are  more  readily  absorbed  than  foods,  wlien 
both  are  brought  to  the  tissues.  Thus  it  is  well  known 
that  of  all  the  salts  the  sulphate  of  copper  is  that  which 
plants  most  readily  absorb  —  and  it  kills  them.  The  spe- 
cial affinities  disappear  as  the  vitality  disappears,  and 
dying  plants  absorb  all  salts  equally. 

*  Ranke,  Die  Lchensbcdingungcn  dcr  Nerven,  18G8,  p.  80. 


18  THE   niYSICAL   BASIS   OF   MIND. 

19.  The  more  the  organism  is  studied,  the  more  evident 
it  will  become  that  the  simple  laws  of  diffusion,  as  pre- 
sented in  anorganisms  rarely  if  ever  take  effect  in  tissues  ; 
in  other  words,  what  is  called  Imbibition  in  Physics  is 
the  somewhat  different  process  of  Absorption  in  Physiol- 
ogy.* The  difference  is  notable  in  this  capital  fact,  that 
whereas  the  physical  diffusion  of  liquids  and  gases  is 
determined  by  differences  of  density,  the  physiological 
absorption  of  liquids  and  gases  is  determined  by  the  mo- 
lecular organization  of  the  tissue,  which  is  perfectly  indif- 
ferent to,  and  resists  the  entrance  of,  all  svibstances  incapa- 
ble of  entering  into  organic  combination,  either  as  aliment 
or  poison.  A  curious  example  of  the  indifference  of  or- 
ganized substances  to  some  external  influences  and  their 
reaction  upon  others,  is  the  impossibility  of  provoking 
ciliary  movement  in  an  epithelial  cell,  during  repose,  by 
any  electrical,  mechanical,  or  chemical  stimuli  except  pot- 
ash and  soda.  Virchow  discovered  that  a  minute  quan- 
tity of  either  of  these,  added  to  the  w^ater  in  which  the 
cell  floated,  at  once  called  forth  the  ciliary  movements. 

20.  The  true  meaning  of  the  resistance  of  Vitality  to 
ordinary  chemical  affinity  is,  that  the  conditions  involved 
in  the  phenomena  of  Vitality  are  not  the  conditions  in- 
volved in  the  phenomena  of  Chemistry ;  in  other  words, 
that  in  the  living  organism  the  substances  are  placed 
under  conditions  different  from  those  in  which  we  observe 
these  substances  when  their  chemical  affinities  are  dis- 
played in  anorganisms.  But  we  need  not  go  beyond  the 
laboratory  to  see  abundant  examples  of  this  so-called  re- 
sistance to  chemical  affinity,  when  the  conditions  are 
altered.  The  decomposition  of  carbonates  by  tartaric  acid 
is  a  chemical  process  which  is  wholly  resisted  if  alcohol 

*  "II  n'y  a  peut  etre  pas  un  seul  phenomeiie  chimique  dans  rorganisme 
qui  se  fasse  par  les  precedes  de  la  chimie  de  laboratoire  ;  en  particulier  i1 
n'y  a  peut  etre  pas  una  oxydation  qui  s'accomplisse  par  fixation  directH 
d'o.xvffene. " —  Claude  Bekxard. 


THE   NATURE   OF   LIFE.  19 

instead  of  water  be  the  solvent  employed.  The  union  of 
sulphur  with  lead  is  said  to  be  due  to  the  affinity  of  the 
one  for  the  other ;  but  no  one  supposes  this  affinity  to 
be  irrespective  of  conditions,  or  that  the  union  will  take 
place  when  any  one  of  these  conditions  is  absent.  If  we 
fuse  a  compound  of  lead  and  iron  in  a  crucible  containing 
sulphur,  we  find  it  is  the  iron,  and  not  the  lead,  whicli 
unites  with  the  sulphur ;  yet  we  do  not  conclude  that 
there  is  a  Crucible  Principle  which  frustrates  chemical 
affinity  and  resists  the  union  of  sulphur  and  lead ;  we 
simply  conclude  that  the  presence  of  the  iron  is  a  condi- 
tion which  prevents  the  combination  of  the  sulphur  with 
the  lead  :  not  until  all  the  iron  has  taken  up  its  definite 
proportion  of  sulphur  will  the  affinity  of  the  lead  come 
into  play.  This  is  but  another  illustration  of  the  law  that 
effects  arc  2^'>'ocessions  of  their  causes,  summations  of  the 
conditions  of  their  existence.  If  the  fire  burns  no  hole  in 
the  teakettle  so  long  as  there  is  water  to  conduct  the  heat 
away,  this  is  not  due  to  any  principle  more  mysterious 
than  the  presence  of  a  readily  conducting  water.* 

*  Dr.  Maddex,  in  his  essay  On  the  Relation  of  Therapeutics  to  Medi- 
cine, 1871,  p.  5,  gives  a  remarkaDle  illustration  of  what  may  be  called  the 
frustration  of  chemical  affinity  effected  by  mechanical  conditions.  "  Be- 
fore calico  can  be  printed,  every  loose  particle  of  cotton  must  be  removed 
from  the  surface  in  order  that  the  colored  inks  may  not  run.  This  re- 
moval is  effected  by  passing  the  calico  over  and  in  contact  with  a  red-hot 
iron  cylinder,  and  by  regulating  the  rapidity  with  which  the  cylinder  re- 
volves, the  intense  heat  burns  off  the  loose  fibres,  yet  does  no  injury  to 
the  woven  cloth.  In  other  words,  the  changes  in  the  relation  of  the  liigh 
temperature  and  tlie  cotton  arc  too  rapid  to  admit  of  the  fibre  combining 
with  the  oxygen.  Let  the  rate  of  revolution  bo  reduced  but  very  little, 
and  the  calico  would  burst  into  flames."  Any  one  who  has  snuffed  a 
candle  with  his  fingers  will  understand  this.  Dr.  Madden  further  in- 
stances certain  fulminates  which  can  be  detonated  in  contact  with  gun- 
cotton  without  causing  it  to  explode  —  the  extreme  rapidity  with  which 
the  fulminates  exj)and  is  too  great  to  enable  the  gun-cotton  to  adjust  its 
movements  to  this  new  motion.  Precisely  the  same  kind  of  thing  occurs 
in  organized  matter.  If  the  rate  of  its  elianges  be  reduced  below  a  cer- 
tain point,  the  ordinary  chemical  affinities  will  assert  themselves. 


20  THE   PHYSICAL   BASIS   OF   MIND. 

21.  In  accordance  with  the  law  of  Causation  just  men- 
tioned, whicli  has  been  expounded  in  detail  in  our  First 
Series  (Vol.  II.  p.  335),  the  special  combinations  of  Matter 
in  organisms  must  present  special  phenomena.  Therefore 
since  the  province  of  Biology  is  that  of  explaining  or- 
ganic phenomena  by  means  of  their  organic  conditions,  it 
must  be  radically  distinguished  from  the  provinces  of 
Pliysics  and  Chemistry,  which  treat  not  of  organized  but 
of  inorganic  matter.  It  is  idle,  it  is  'vvorse,  for  it  is  mis- 
leading, to  personify  the  organic  conditions,  known  and 
inferred,  in  a  Vital  Principle  ;  idle,  because  we  might  with 
equal  propriety  personify  the  conditions  of  crystallization 
in  a  Crystal  Principle ;  misleading,  because  the  artifice  is 
quickly  dropped  out  of  sight,  and  the  abstract  term  then 
becomes  accepted  as  an  entity,  supposed  to  create  or  rule 
the  phenomena  it  was  invented  to  express. 

22.  Inquirers  are  but  too  apt  to  misconceive  the  value 
of  Analysis,  which  is  an  artifice  of  Method  indispensable 
to  research,  though  needing  the  complementary  rectifica- 
tion by  Synthesis  before  a  real  explanation  can  be  reached. 
Analysis  decomposes  the  actual  fact  into  ideal  factors, 
separates  the  group  into  its  components,  and  considers 
each  of  these,  not  as  it  exists  in  the  group,  in  the  reality, 
but  as  it  exists  when  theoretically  detached  from  the 
others.  The  oxygen  and  hydrogen  into  which  water  is 
decomposed  did  not  exist  as  these  gases  in  the  water ;  the 
albumen  and  phosphate  we  extract  from  a  nerve  did  not 
exist  as  isolated  albumen  and  phosphate  in  the  nerve,  they 
were  molecularly  combined.  In  like  manner  the  physical 
and  chemical  processes  which  may  analytically  be  inferred 
in  vital  processes  do  not  really  take  place  in  the  same  way 
as  out  of  the  organism.  The  real  process  is  always  a  vital 
process,  and  must  be  explained  by  the  synthesis  of  all  the 
co-operant  conditions.  The  laws  of  Physics  and  Chemis- 
try formulate  abstract  expressions  of  phenomena,  where- 


THE  NATURE   OF  LIFE.  21 

ever  and  whenever  these  appear,  without  reference  to  the 

modes  of  production  ;  and  in  this  sense  the  movement  of 
a  limb  is  no  less  a  case  of  Dynamics  than  tlie  movement 
of  a  pulley  —  the  decomposition  of  a  tissue  is  a  case  of 
Chemistry  no  less  than  the  decomposition  of  a  carbonate  ; 
the  electromotor  phenomena  observed  in  muscle  are  as 
purely  physical  as  those  observed  in  a  telegraph.  But 
when  a  biologist  has  to  explain  the  movements  of  the 
limbs,  or  the  decompositions  of  tissues,  he  has  to  deal  with 
the  phenomena  and  their  modes  of  production,  he  has  a 
particular  group  before  him,  and  must  leave  out  noth- 
ing that  is  characteristic  of  it.  The  movements  of  the 
pulley  do  not  depend  on  Contractility  and  Sensibility, 
which  in  turn  depend  on  Nutrition.  The  decomposition 
of  the  carbonate  does  not  depend  on  conditions  resem- 
blino-  those  of  a  livinf^  tissue.  Vaucanson's  duck  was  sur- 
prisingly  like  a  living  duck  in  many  of  its  movements ; 
but  in  none  of  its  actions  was  there  any  real  similarity  to 
the  actions  of  a  bird,  because  the  machine  was  unlike  an 
organism  in  action.  The  antithesis  of  mechanism  and 
organism  will  be  treated  of  in  §  78. 

23.  We  conclude,  then,  that  defining  physical  phenom- 
ena as  the  movements  which  take  place  without  change 
of  structure,  and  chemical  phenomena  as  the  movements 
with  change  of  structure,  although  both  classes  may  be 
said  to  take  place  in  the  organism,  and  to  be  the  primary 
conditions  on  which  organic  phenomena  depend,  they  ^o 
not  embrace  the  whole  of  the  conditions,  nor  are  the  sci- 
ences which  formulate  them  capable  of  formulating  either 
the  special  phenomena  characteristic  of  organisms  or  their 
special  modes  of  production.  The  biologist  will  employ 
chemical  and  yjliysical  analysis  as  an  essential  part  of  his 
method ;  but  he  will  always  rectify  what  is  artificial  in 
this  procedure,  by  sul)ordinating  the  laws  of  Pliysics  and 
Chemistry  to  the  la\\'s  of  Biology  revealed  in  the  syn- 


22  THE  niYsicAL  basis  of  mind. 

thetic  observation  of  the  organism  as  a  whole.  The  recti- 
fication, here  insisted  on,  will  be  recognized  as  peculiarly 
urgent  in  Psychology,  which  has  greatly  suffered  from  the 
misdirection  of  Analysis. 

24.  No  one  will  misunderstand  this  specialization  of 
Biology  to  mean  a  separation  of  Life  from  tlie  series 
of  objective  phenomena,  and  the  introduction  of  a  new 
entity ;  the  specialization  points  to  a  Mode  of  Existence. 
All  classifications  are  artifices,  but  they  have  their  objec- 
tive grounds  ;  the  ground  of  difference  on  which  Biology 
is  separated  from  Chemistry  and  Pliysics,  though  all 
three  may  be  merged  in  a  common  identity,  is  such  as  to 
justify  the  term  radical.  A  vital  process  is  no  more  to 
be  considered  physico-chemical,  because  physico-chemical 
conditions  are  j)resuj)posed  in  it,  than  a  feeling  is  to  be 
considered  a  nutritive  process,  because  Nutrition  is  pre- 
supposed in  all  Feeling.  Organic  substances  have  been 
made  by  chemists,  and  inorganic  "  cells  "  have  also  been 
made ;  but  these  substances  were  not  organized,  these 
"  cells  "  would  not  live.  The  germ-cell  is  the  workshop 
of  generation,  the  secreting-cell  the  workshop  of  secre- 
tion, the  muscle-cell  the  workshop  of  contraction.  What 
is  required  over  and  above  organic  substances  and  cell- 
forms,  is  that  special  state  called  organization.     See  §  49. 

Those  who  contemplate  the  manifestations  without  also 
taking  into  account  their  modes  of  production  may  see 
nothing  but  physico-chemical  facts  in  vital  facts.  It  is 
by  a  similar  limitation  of  the  point  of  view  that  A'itality 
is  often  confounded  with  IMovement,  and  portions  of 
organic  matter  are  said  to  live,  simply  on  the  evidence 
of  their  movements.* 

*  I  am  often  reminded  of  the  sui-prising  movements  of  particles  of 
carbonate  of  lime  in  water  which  mj'  friend  Professor  Peeyek  showed 
me  during  a  visit  to  Bonn.  He  had  removed  one  of  the  concretions,  usu- 
ally found  in  connection  with  nerves  along  the  spine  of  old  frogs,  and 


THE  NATUKE  OF  LIFE.  23 

crushed  it  in  water  ;  under  the  microscope  the  seeming  spontaneity  and 
variety  of  the  movements  of  the  particles  was  such  that  had  we  not 
known  their  origin  we  should  certainly  have  attributed  them  to  vitality  : 
no  infusoria  could  have  moved  with  more  seeming  spontaneity.  It  is 
hardly  physiological  to  conclude  that  because  fragments  of  tissue  mani- 
fest amcebiform  movements  therefore  they  are  alive  (Stricker,  art.  Die 
Zcllc  in  his  Handbuch  der  Lchre  von  den  Geweben,  1868,  p.  7),  or  that  the 
heart  removed  from  the  body  is  alive  because  it  still  beats.  Lieber- 
KUHN,  Ueber  Bcwegungsersclieinungen  der  Zellen,  1870,  pp.  357-359, 
cites  examples  of  such  movements  in  undeniably  dead  substances.  For 
Life,  we  demand  not  only  Movement,  but  Functional  Activity. 


24  THE  PHYSICAL  BASIS  OF  MIND. 


CHAPTEE    II. 

DEFINITIONS   OF  LIFE. 

25.  Biology,  the  science  of  Life,  being  thus  assigned 
its  place  in  the  hierarchy  of  objective  laws,  we  now  pro- 
ceed to  consider  what  the  term  Life  symbolizes. 

By  a  large  preliminary  simplification.  Life  may  be  de- 
fined as  the  mode  of  existence  of  an  organism  in  relation 
to  its  inedium.  To  render  this  of  any  value,  however,  a 
clear  conception  of  the  organism  is  first  indispensable  ; 
and  this  must  be  preceded  by  an  examination  of  the  vari- 
ous attempts  to  define  life  in  anticipation  of  such  a  clear 
conception. 

26.  Every  phenomenon,  or  group  of  phenomena,  may  be 
viewed  under  two  aspects  —  the  statical,  which  considers 
the  conditions  of  existence  ;  and  the  dynamical,  which  con- 
siders these  conditions  in  their  resultant, — in  their  action. 
The  statical  definition  of  Life  will  express  the  connexus 
of  the  properties  of  organized  substance,  all  those  con- 
ditions, of  matter,  form,  and  texture,  and  of  relation  to 
external  forces,  on  which  the  organism  depends.  These 
various  conditions,  condensed  into  a  single  symbol,  con- 
stitute Vitality  or  Vital  Force,  and  are  hence  taken  as  the 
Cause  of  vital  phenomena.  Tlie  dynamical  definition 
will  express  the  connexus  of  Functions  and  Faculties  of 
the  organism,  which  are  the  statical  properties  of  organ- 
ized substance  in  action,  under  definite  relations. 

It  is  obvious  that  the  term  Life  must  vary  with  the 
varying  significates  it  condenses, —  every  variation  in  the 
complexity  of  the  organism  will  bring  a  corresponding 


THE   NATUEE   OF   LIFE.  25 

fulness  in  the  signification  of  the  term.  The  life  of  a 
l)lant  is  less  significant  than  the  life  of  an  animal ;  and 
tlie  life  of  a  mollusc  less  than  that  of  a  fish.  But  not 
only  is  the  term  one  of  varying  significance,  it  is  always 
an  abstract  term  which  drops  out  of  sight  particular  con- 
crete differences,  registering  only  the  universal  resem- 
blances. 

27.  It  would  be  a  profitless  labor  to  search  out,  and  a 
wearisome  infliction  to  set  down,  the  various  definitions 
which  have  been  proposed  and  accepted;  but  certain 
characteristic  examples  may  be  selected.  All  that  I  am 
acquainted  with  belong  to  two  classes :  1°,  the  mcta-Ythj- 
siological  hypothesis  of  an  ea^^ra-organic  agent,  animating 
lifeless  matter  by  unknown  powers  ;  2°,  the  physiological 
hypothesis  which  seeks  the  cause  of  the  phenomena  (i.  e. 
the  conditions)  icithin  the  organism  itself,  —  a  group  of 
conditions  akin  to  those  manifested  elsewhere,  but  differ- 
ently combined.  The  first  hypotheses  are  known  under 
the  names  of  Animism  and  Vitalism,  —  more  commonly 
the  latter.  The  second  are  known  as  Organicism  and 
Materialism,  —  but  the  latter  term  only  applies  to  some 
of  the  definitions. 

28.  Under  Vitalism  are  included  all  the  hypotheses  of 
a  soul,  a  spirit,  an  archai'us,  a  vital  principle,  a  vital  force, 
a  nisus  formativus,  a  plan  or  divine  idea,  which  have  from 
time  to  time  represented  the  metaphysical  stage  of  Biol- 
ogy. The  characteristic  of  that  stage  is  the  personifi- 
cation of  a  mystery,  accompanied  by  the  persuasion  that 
to  name  a  mystery  is  to  explain  it.  In  all  sciences  when 
processes  are  imperfectly  observed,  the  theory  of  the  pro- 
cesses (which  is  a  systematic  survey  of  the  available  evi- 
dence marshalled  in  the  order  of  causal  dependence)  is 
supplemented  by  JiypotJiesis,  which  fills  up  witli  a  guess 
the  gap  left  by  observation.     The  difference  between  the 

VOL.  ni.  2 


26  THE  PHYSICAL  BASIS   OF   MIND. 

metaphysical  and  the  positive  stages  of  a  science  lies  in 
the  kind  of  guess  thus  introduced  to  supplement  theory, 
and  the  degree  of  reliance  accorded  to  it.  I  have  more 
than  once  insisted  on  the  scientific  canon  that  "  to  be 
valid,  an  explanation  must  be  expressed  in  terms  of 
phenomena  already  observed  "  ;  now  it  is  quite  clear  that 
most  of  the  extra-organic  hypotheses  do  not  fulfil  this  con- 
dition ;  no  one  having  ever  observed  a  spirit,  an  archseus, 
or  a  vital  principle ;  but  only  imagined  these  agents  to 
explain  the  facts  observed.  As  an  example  of  the  dif- 
ference, and  a  proof  that  the  value  of  an  hypothesis  does 
not  rest  on  the  facility  with  which  it  connects  observa- 
tions, and  seems  to  explain  them,  take  the  three  hypoth- 
eses of  animal  spirits,  nervous  fluid,  and  electricity,  by 
which  neural  processes  have  been  explained.  The  ani- 
mal spirits  are  imaginary ;  the  nervous  fluid  is  without  a 
basis  in  observation,  no  evidence  of  such  a  fluid  having 
been  detected  ;  but  electricity  (or,  speaking  rigorously,  the 
movements  classed  as  electrical),  although  not  proved  to 
be  the  agent  in  nerve-action,  is  proved  to  exist  in  nerves 
as  elsewhere,  and  its  modes  of  operation  are  verifiable. 
It,  therefore,  and  it  alone  of  the  three  h}^otheses,  is  in 
conformity  with  the  scientific  canon.  It  may  not,  on  full 
investigation,  meet  all  requirements  ;  it  may  be  rejected 
as  imperfect ;  but  it  is  the  kind  of  guess  which  scientific 
theory  demands. 

The  second  difference  noticeable  between  the  meta- 
physical and  the  positive  stages  is  the  degree  of  reliance 
accorded  to  hypothesis  ;  which  is  very  much  the  same  as 
that  noticeable  in  the  uncritical  and  critical  attitudes  of 
untrained  and  trained  intellects.  The  one  accepts  a  guess 
as  if  it  were  a  proof ;  is  fascinated  by  the  facility  of  link- 
ing together  isolated  observations,  and,  relying  on  the 
guess  as  truth,  proceeds  to  deduce  conclusions  from  it ; 
the  other  accepts  a  guess  as  an  aid  in  research,  trying  by 


THE   NATUEE   OF   LIFE.  27 

its  aid  to  come  upon  some  observation  wliicli  will  reveal 
the  hidden  process ;  but  careful  never  to  allow  the  guess 
to  siq^erscde  observation,  or  to  form  a  basis  of  deductions 
not  immediately  verified. 

29.  A  glance  at  the  metaphysiological  definitions  will 
detect  both  the  kind  of  guess  and  the  kind  of  reliance 
which  prevailed.  The  mystery  was  not  simply  recog- 
nized, it  was  personified  as  an  entity :  Will  and  Intelli- 
gence were  liberally  accorded  to  it,  for  it  was  supposed  to 
shape  matter,  and  direct  force  into  predestined  paths  by 
prescience  of  a  distant  end.  The  observed  facts  of  the 
egg  passing  through  successive  changes  into  a  complex 
organism  were  so  marvellous,  so  unlike  any  facts  observ- 
able in  the  inorganic  world,  that  they  seemed  to  demand 
a  cause  drawn  from  higher  sources.  The  mystery  of  life 
obtruded  itself  at  every  turn.  It  was  named,  and  men 
fancied  it  explained.  But  in  truth  no  mj^stery  is  got  rid 
of  by  explanation,  however  valid  ;  it  is  only  shifted  farther 
back.  Explanation  is  the  resolution  of  a  complex  phe- 
nomenon into  its  conditions  of  existence  —  the  product 
is  reduced  to  its  factors ;  the  explanation  is  final  when 
this  resolution  has  been  so  complete  that  a  reconstruction 
of  the  product  is  possible  from  the  factors.  The  vast  ma- 
jority of  explanations  —  especially  in  the  organic  region 
—  are  no  more  than  what  mathematicians  call  "  a  first 
approximation."  It  is  through  successive  approximations 
that  science  advances ;  but  even  when  tlie  final  stage  is 
reached  a  mystery  remains.  We  may  know  that  certain 
elements  combine  in  certain  proportions  to  produce  cer- 
tain substances ;  but  why  they  produce  these,  and  not 
different  substances,  is  no  clearer  than  why  muscles  con- 
tract or  organisms  die.  This  Why  is,  however,  an  idle 
fpiestion.  That  alone  which  truly  concerns  us  is  the  How, 
and  not  the  Why. 

30.  Biology  is  still  a  long  way  off  the  How.     But  it 


28  Tin-:  thysical  basis  of  mind. 

can  boast  of  many  approximations ;  and  its  theories  are 
to  be  tested  by  the  degree  of  approximation  they  effect. 
In  this  light  the  physiological,  m/ra-organic,  hypotheses 
manifestly  have  the  advantage.  Many  of  them  are  in- 
deed vei-y  unacceptable  ;  they  are  guided  by  a  mistaken 
conception  of  the  truths  reached  by  Analysis.  For  when 
men  first  began  to  discard  the  extra-organic  hypotheses, 
and  to  look  into  the  organism  itself,  they  were  so  much 
impressed  by  the  mechanical  facts  observed,  that  they 
endeavored  to  reduce  all  the  phenomena  to  Mechanics. 
Tlie  circulation  became  simply  a  question  of  hydraulics. 
Digestion  was  explained  as  trituration.  The  chemists 
then  appeared,  and  their  shibboleths  were  "  affinities " 
and  "oxidations."  With  Bichat  arose  the  anatomical 
school,  which  decomposing  the  organism  into  organs,  the 
organs  into  tissues,  and  these  tissues  into  their  elements, 
sought  the  analytical  conditions  of  existence  of  the  or- 
ganism in  the  properties  of  these  tissues,  and  the  functions 
of  these  organs.  The  extra-organic  agent  was  thus  finally 
shown  to  be  not  only  a  fiction,  but  a  needless  fiction. 

Every  student  of  the  history  of  the  science  will  note 
how  from  the  very  necessities  of  the  case  the  metaphysi- 
ologists,  without  relinquishing  their  Vital  Principle,  have 
been  led  more  and  more  to  enter  on  the  track  of  the 
physiologists,  pursuing  their  researches  more  and  more 
into  the  processes  going  on  in  the  organism,  and  assigning 
more  and  more  causal  efficiency  to  these,  with  a  corre- 
sponding restriction  of  the  province  of  their  extra-organic 
cause.  Hence  in  the  ranks  of  the  vitalists  have  been 
found  some  of  the  very  best  observers  and  theorists ;  but 
they  were  such  in  despite  of,  and  not  in  consequence  of, 
their  hypothesis,  which  was  only  invoked  by  them  when 
evidence  was  at  fault.  Nor,  unscientific  as  vitalism  is, 
can  we  deny  tliat  it  has  been  so  far  serviceable  to  the 
science,  that  it   has   corrected   the   materialist   error  of 


THE   NATUItE   OF   LIFE.  29 

endeavoring  to  explain  organic  phenomena  by  physico- 
chemical  laws ;  and  has  persistently  kept  in  view  the 
radical  difference  between  organic  and  inorganic. 

31.  These  remarks  may  justify  a  selection  of  defini- 
tions, classified  under  the  two  heads.  Tlie  selection  is  fitly 
opened  by  the  Aristotelian  definition  which  prevailed  for 
centuries. 

Aristotle  distinguishes  Life,  which  he  says  means  "  the 
faculties  of  self-nourishment,  seK-development,  and  self- 
decay,"  from  the  Vital  Principle.  Every  natural  body 
manifestiug  life  may  be  regarded  as  an  essential  existence 
(over la);  but  tlicn  it  is  an  existence  only  as  a  synthesis  (<»9 
avvOe-rr]) ;  and  since  an  organism  is  such  a  synthesis,  being 
possessed  of  Life,  it  cannot  be  the  Vital  Principle  {"y^v^fri). 
Therefore  it  follows  that  the  Vital  Principle  must  be  an 
essence,  as  being  the  Form  of  a  natural  body  holding  life 
in  'potentiality.  The  Vital  Principle  is  the  primary  reality 
of  an  organism.  "  It  is  therefore  as  idle  to  ask  whether 
the  Vital  Principle  and  Organism  are  one,  as  whether  the 

wax  and  the  impress  on  it  are  one Thus  if  an  eye 

were  an  animal,  Vision  would  be  its  Vital  Principle :  for 
Vision  is,  abstractedly  considered,  the  essence  of  the  eye ; 
but  the  eye  is  the  body  of  Vision,  and  if  Vision  be  want- 
ing, then,  save  in  name,  it  is  no  longer  an  eye." 

Apart  from  certain  metaphysical  implications,  inevitable 
at  that  period,  there  is  profound  insight  in  this  passage. 
His  adversary  Telesio  quite  misconceives  the  meaning 
liere  assigned  to  the  Vital  Principle.* 

32.  Let  us  pass  over  all  tlie  intermediate  forms  of  the 
liypotliesis,  and  descend  to  Kant,  who  defines  Life  "an 
internal  principle  of  action  "  (this  does  not  distinguish  it 

*  Telesiu.s,  De  Natura  Rerum,  1586,  V.  184.  Telf.sio  nii^'lit  have 
1)oon  savf'd  from  the  mistake  had  he  attended  to  what  Niphus  had  .said 
on  the  point  in  liis  Exposilio  suUilissimn,  1559,  p.  245.  Conip.  also 
PiiiLELi'iius,  Epist.  Familiarum,  1502,  p.  253,  verso. 


30  THE  riiYsic.a,  basis  of  mind. 

from  fermentation)  ;  an  organism  he  says  is  "  that  in 
which  every  part  is  at  once  means  and  end."  "  Each  part 
of  the  living  body  has  its  cause  of  existence  in  the  whole 
organism ;  whereas  in  non-living  bodies  eacli  part  has  its 
cause  in  itself."  Johannes  ]\Iuller  adopts  a  similar  view : 
"  The  harmonious  action  of  the  essential  parts  of  the  indi- 
vidual subsist  only  by  the  influence  of  a  force,  the  opera- 
tion of  which  is  extended  to  all  parts  of  the  body,  and 
does  not  dej^end  on  any  single  parts  ;  this  force,  must  exist 
before  tJie  parts,  which  ai-e  in  fact  formed  by  it  during  the 

development  of  the  embryo The  vital  force  inherent 

in  them  generates  from  the  organic  matter  the  essential 
organs  which  constitute  the  whole  being.  This  rational 
creative  force  is  exerted  in  every  animal  strictly  in  accord- 
ance with  what  the  nature  of  each  requires." 

33.  This  is  decidedly  inferior  to  Aristotle,  who  did  not 
confound  the  vegetative  with  the  rational  principle.  It 
rests  on  the  old  metaphysical  error  of  a  vis  meclicatrix,  an 
error  which  cannot  sustain  itself  against  the  striking  facts 
wdiich  constantly  point  to  a  vis  dcstriictrix,  a  destructive 
tendency  quite  as  inexorable  as  the  curative  tendency. 
And  the  experimental  biologist  soon  becomes  impressed 
with  the  fact  that  the  tissues  have  indeed  a  sclcctim  action, 
by  which  from  out  the  nutrient  material  only  these  sub- 
stances are  assimilated  which  will  enter  into  combination 
with  them  ;  but  this  selective  action  is  fatal,  no  less  than 
reparative  :  substances  which  poison  the  tissue  are  taken 
up  as  readily  as  those  which  nourish  it.  The  idea  of 
prescience,  therefore,  cannot  be  sustained  ;  it  is  indeed 
seldom  met  with  now  in  the  M'ritings  of  any  but  the 
Montpellier  school,  who  continue  the  traditions  of  Stalil's 
teaching.  It  has  been  so  long  exploded  elsewhere  that 
one  is  surprised  to  find  an  English  physiologist  clinging 
to  a  modification  of  it  —  I  mean  Dr.  Lionel  Beale,  who 
repeatedly  insists  on  Life  as  "  a  peculiar  Force,  tempera- 


THE   NATURE   OF   LIFE,  31 

rily  associated  with  matter,"  a  "power  capable  of  con- 
trolling and  directing  both  matter  and  force,"  an  "  undis- 
covered form  of  force  having  no  connection  ivith  primary 
energy  or  motion"  "  The  higher  phenomena  of  the  ner- 
vous system  are  probably  due  primarily  to  the  movements 
of  the  germinal  matter  due  to  vital  power,  which  vital 
power  of  this  the  highest  form  of  germinal  matter  is  in 
fact  the  living  /." 

34.  Apart  from  the  primary  objection  to  all  these 
definitions,  namely,  that  they  seek  to  express  organic 
phenomena  in  terms  of  an  extra-organic  principle,  to 
formulate  the  facts  observed  in  terms  of  a  cause  inferred, 
there  is  the  fatal  objection  that  they  speak  confidently 
on  what  is  avowedly  unknown.  If  the  force  be,  as  Dr. 
Beale  says,  "undiscovered,"  on  what  grounds  can  he 
assert  that  it  has  no  connection  with  the  forces  which 
are  known  ?  All  that  the  observed  facts  warrant  is  the 
assertion  that  organic  phenomena  are  special  (which  no 
one  denies),  and  must  therefore  depend  on  special  com- 
binations of  matter  and  force.  But  on  this  ground  we 
might  assume  a  crystallizing  Force,  and  a  coagulating 
Force,  having  no  connection  with  the  molecular  forces 
manifested  elsewhere :  these  also  are  special  phenomena, 
not  to  be  confounded  with  each  other. 

35.  Schelling  defines  Life  as  "  a  principle  of  individua- 
tion "  and  a  "  cycle  of  successive  changes  determined  and 
fixed  l)y  this  internal  principle."  Which  is  so  vague 
tliat  it  may  be  applied  in  very  different  senses.  Bichat's 
celebrated  definition  (which  is  only  a  paraphrase  of  a 
sentence  in  Stahl),  "  the  sum  of  the  functions  which  re- 
sist Death,"  altliough  an  endeavor  to  express  the  facts 
from  the  Intra-organic  point  of  view,  is  not  only  vague, 
but  misrepresents  one  of  the  cardinal  conditions,  by  treat- 
ing the  External  Medium  as  antagonistic  to  Lift!,  wliercas 
Life  is  only  possible  in  the  relation  to  a  Medium. 


32  THE  PHYSICAL   BASIS   OF  mND. 

36.  Were  it  not  so  vague,  the  definition  proposed  by 
Dugcs  and  Beclard  would  be  unexceptionable  :  the  former 
says  it  is  "  the  special  activity  of  organized  beings " ; 
the  latter,  "  the  sum  of  the  phenomena  proper  to  organ- 
ized bodies."  When  supplemented  by  a  description  of 
organized  bodies,  these  formuhe  are  compendious  and 
exact.  The  same  remark  applies  to  the  definition  of 
Lamarck:  "that  state  of  things  which  permits  organic 
movements;  and  these  movements,  which  constitute  active 
life,  result  from  a  stimulus  which  excites  them." 

37.  De  Blainville,  and  after  him  Comte  and  Charles 
Eobin,  define  it  thus :  "  Life  is  the  twofold  internal  move- 
ment of  composition  and  decomposition  at  once  general 
and  continuous."  This,  excellent  as  regards  what  is 
called  vegetal  life,  is  very  properly  objected  to  by  Mr. 
Herbert  Spencer  in  that  it  excludes  those  nervous  and 
muscular  functions  which  are  the  most  conspicuous  and 
distinctive  of  vital  phenomena.  The  same  objection  must 
be  urged  against  Professor  Owen's  definition :  "  Life  is  a 
centre  of  intussusceptive  assimilative  force  capable  of 
reproduction  by  spontaneous  fission." 

38.  In  1853,  after  reviewing  the  various  attempts  to 
fexpress  in  a  sentence  what  a  volume  could  only  approxi- 
/mately  expound,  I  proposed  the  following :  "  Life  is  a  se- 
'ries  of  definite  and  successive  changes,  both  of  structure 

and  composition,  which  take  place  within  an  individual 
without  destroying  its  identity."  This  has  been  criticised 
by  Mr.  Herbert  Spencer  and  by  Dr.  Lionel  Beale,  and  if 
I  had  not  withdrawn  it  before  their  criticisms  appeared, 
I  should  certainly  have  modified  and  enlarged  it  after- 
wards. I  mention  it,  however,  because  it  is  an  approach 
to  a  more  satisfactory  formula  in  so  far  as  it  specifies  two 
cardinal  characteristics  distinguishing  organisms  from  all 
anorganisms,  namely,  the  incessant  evolution  through 
definite  stages,  and  the  preservation  of  specific  integrity 


THE  NATURE   OF  LIFE.  33 

throughout  the  changes ;  not  only  the  organism  as  a 
whole  is  preserved  amidst  incessant  molecular  change, 
but  each  tissue  lives  only  so  long  as  the  reciprocal  molec- 
ular composition  and  decomposition  persist.  On  both  of 
these  points  I  shall  have  to  speak  hereafter.  The  defini- 
tion, however,  is  not  only  defective  in  its  restriction  to 
the  molecular  changes  of  Nutrition,  taking  no  account  of 
the  Properties  and  Functions  of  the  organism ;  but  defec- 
tive also  in  giving  no  expression  to  equally  important 
relations  of  the  organism  to  the  medium. 

39.  This  last  point  is  distinctly  expressed  in  Mr.  Spen- 
cer's definition:  "Life  is  the  continuous  adjustment  of 
internal  relations  to  external  relations."  Considered  as  a 
formula  of  the  most  general  significance,  embracing  there- 
fore what  is  common  to  all  orders  of  vital  phenomena, 
this  is  the  best  yet  proposed.*  If  I  propose  another  it 
will  not  be  to  displace  but  to  run  alongside  with  Mr. 
Spencer's ;  and  this  only  for  more  ready  convenience. 
Before  doing  so  I  must  say  a  few  words  by  way  of  clear- 
ing the  ground. 

40.  What  does  the  term  Life  stand  for  ?  What  are 
the  concrete  significates  of  this  abstract  symbol  ?  As 
before  stated,  it  is  sometimes  a  compendious  shorthand 
for  the  special  phenomena  distinguishing  living  from  non- 
living bodies ;  and  sometimes  it  expresses  not  these  ob- 
served phenomena,  but  their  conditions  of  existence,  which 
are  by  one  school  personified  in  an  abstract  and  extra- 
organic  cause.     Thus  the  life  of  an  animal,  a  man,  or  a 

*  The  authorities  just  cited  are  Aristotle,  De  Anima.,  Lib.  IL  c.  L 
Kant,  Krilik  dcr  Urthcilskraft.  Muller,  Physiology.  Beale,  Bioplasm, 
and  Introduction  to  Todd  and  Boioman's  Anatomy.  Sciiem.ing,  Erstcr 
Entvnirf,  and  Transcendent.  Idcalisnius.  Bichat,  Rcclierchcs  siir  la  Vie 
et  la  Mart.  Stahl,  Tlieoria  Vera  Medica.  DuGi;.s,  Physiologic  Com- 
parSc.  Bi^xlard,  Anatomic  G&nirah.  Lamarck,  Philosophic  Zoo- 
logiquc.  Comte,  Cours  de  Philosophic  Positive.  Owen's  Htmterian 
Lectures,  1854.     Herbert  Spencer,  Principles  of  Biology. 

2*  0 


34  THE  PHYSICAL   BASIS   OF   MIND. 

nation,  means  —  1°,  the  special  manifestations  of  these 
organisms,  and  groups  of  organisms ;  or  2°,  the  causes 
which  produce  these  manifestations.  We  are  often  mis- 
understood by  others,  and  sometimes  vague  to  ourselves, 
when  we  do  not  bear  these  two  different  meanings  in 
view.  It  was  probably  some  sense  of  this  which  made 
Aristotle  distinguish  Vitality  from  Life,  as  that  of  the 
one  uniform  cause  separated  from  its  multiple  effects ; 
it  was  certainly  the  motive  of  Fletcher,  who  thus  ex- 
pressly limits  the  meanings :  "  Vitality  or  Irritability,  the 
property  which  characterizes  organized  beings  of  being 
acted  on  by  certain  powers  otherwise  than  either  strictly 
mechanically  or  strictly  chemically ;  Life,  the  sum  of  the 
actions  of  organized  beings  resulting  directly  from  their 
vitality  so  acted  on."  * 

Vitality  and  Life  being  thus  discriminated  as  the  stat- 
ical and  the  dynamical  aspects  of  the  organism,  we  find 
in  relation  to  the  former  two  radically  opposed  concep- 
tions :  the  metaphysiological  or  extra-organic,  and  the 
physiological  or  intra-orgauic.  The  first  conceives  Vi- 
tality to  be  a  Vital  Principle,  or  extra-organic  agent, 
sometimes  a  soul,  spirit,  archseus,  idea,  and  sometimes  a 
force,  which  easily  becomes  translated  into  a  property. 

The  conception  of  an  entity  must  be  rejected,  because 
it  is  metempirical  and  unverifiable,  §  34.  The  concep- 
tion of  a  force  must  be  rejected,  because  it  is  irrecon- 
cilable wdth  any  definite  idea  we  have  of  force.  What 
the  term  Force  signifies  in  Physics  and  Chemistry,  name- 
ly, mass  animated  by  velocity,  or  directed  pressure,  which 
is  the  activity  of  the  agent,  —  is  precisely  that  w^hich 
these  vitalists  pertinaciously  exclude.  They  assume  a 
force  which  has  nothing  in  common  with  mass  and  ve- 
locity ;  which  is  not  a  resultant,  hut  a  principle ;  which 

*  Fletcher,  as  quoted  by  Drtsdale,  Life  and  tlie  Equivalence  of 
Force,  Part  II.  p.  120. 


THE  NATURE   OF  LIFE.  35 

instead  of  being  a  directed  quantity,  is  itself  autonomous 
and  directive,  shaping  matter  into  organization,  and  en- 
dowing it  with  powers  not  assignable  to  matter.  If  this 
vital  force  has  any  mass  at  its  back,  it  is  a  spiritual 
mass ;  if  it  is  directed,  the  direction  issues  from  a  "  ]\iind 
somewhere."  Now  this  conception  is  purely  metempir- 
ical.  Not  only  is  it  inexact  to  speak  of  Vitality  as  a 
force,  it  is  almost  equally  inexact  to  speak  of  it  as  a 
property ;  since  it  is  a  term  which  includes  a  variety  of 
properties ;  and  when  Fletcher  assigns  the  synonym  of 
Irritability,  this  at  once  reveals  the  inexactness ;  for 
beside  this  property,  we  must  place  Assimilation,  Evo- 
lution, Disintegration,  Eeproduction,  Contractility,  and 
Sensibility,  —  all  characteristic  properties  included  in  Vi- 
tality. 

41.  Having  thus  rejected  the  conceptions  of  entity, 
force,  and  projDerty,  we  are  left  in  jDresence  of — 1°,  the 
organic  conditions  as  the  elements,  and  2°,  of  their  syn- 
thesis (in  the  state  called  organization)  as  the  personified 
principle.  Vital  forces,  or  the  vital  force,  if  we  adopt 
the  term  for  brevity's  sake,  is  a  symbol  of  the  conditions 
of  existence  of  organized  matter  ;  and  since  organisms  are 
specially  distinguishable  from  anorganisms  by  this  spe- 
ciality of  their  synthesis,  and  not  by  any  difference  in 
the  nature  of  the  elements  combined,  this  state  of  organ- 
ization is  the  "  force  "  or  "  principle  "  of  which  we  are  in 
quest.  To  determine  what  Life  means,  we  must  observe 
and  classify  the  phenomena  presented  by  living  beings. 
To  determine  what  Vitality  —  or  organization  —  means, 
we  must  observe  and  classify  the  processes  which  go  on 
in  organized  substances.  These  will  occupy  us  in  the 
succeeding  chapters ;  here  I  may  so  far  anticipate  as  to 
propose  the  following  definitions :  — 

42.  Life  is  the  functional  activity  of  an  organism  in 
relation  to  its  medium,  as  a  synthesis  of  three  terms  : 


36  THE  niYsicAL  basis  of  mind. 

Structure,  Aliment,  and  Instrument ;  it  is  the  sum  of 
functions  which  are  the  resultants  of  Vitality ;  Vitality 
being  the  sum  of  the  properties  of  matter  in  the  state  of 
organization. 

43.  Vital  phenomena  are  the  phenomena  manifested  in 
organisms  when  external  agencies  disturb  tlieir  molecular 
equilibrium ;  and  hy  organisms  when  they  react  on  ex- 
ternal objects.  Thus  everything  done  in  an  organism, 
or  by  an  organism,  is  a  vital  act,  although  physical  and 
chemical  agencies  may  form  essential  components  of  the 
act.  If  I  shrink  when  struck,  or  if  I  wliip  a  horse,  the 
blow  is  in  each  case  physical,  but  the  shrinking  and  the 
striking  are  vital. 

Every  part  of  a  living  organism  is  therefore  vital,  as 
pertaining  to  Life ;  but  no  part  has  this  Life  when  iso- 
lated ;  for  Life  is  the  synthesis  of  all  the  parts  :  a  feder- 
ation of  the  organs  when  the  organism  is  complex,  a  fed- 
eration of  the  organic  substances  when  the  organism  is  a 
simple  cell. 

44.  All  definitions,  although  didactically  placed  at  the 
introduction  of  a  treatise,  are  properly  the  final  expression 
of  the  facts  which  the  treatise  has  established,  and  they 
cannot  therefore  be  fully  apprehended  until  the  mind  is 
familiarized  w'itli  the  details  they  express.  Much,  there- 
fore, which  to  the  reader  may  seem  unintelligible  or 
questionable  in  the  foregoing  definition,  must  be  allowed 
to  pass  until  he  has  gone  through  the  chapters  which 
follow. 


THE   NATURE   OF   LIFE.  37 


CHAPTEE   III. 

ORGANISM,  ORGANIZATION,  AND  ORGANIC  SUBSTANCE. 

45.  There  is  a  marked  difference  between  organic  and 
OTg&niscd  substances.  The  organic  are  non-living,  though 
capable  of  living  when  incorporated  in  organized  tissue 
(albumen  is  such  a  substance) ;  or  they  may  be  incapable 
of  living  because  they  have  lived,  and  are  products  of 
waste,  e.  g.  urea.  The  organized  substance  is  a  specific 
combination  of  organic  substances  of  various  kinds,  a 
combination  which  is  organization.  Any  organized  sub- 
stance is  therefore  either  an  independent  organism,  or 
part  of  a  more  complex  organism.  Protoplasm,  either  as 
a  separate  organism  or  as  a  constituent  of  a  tissue,  is 
organized  substance. 

Organic  substances  are  numerous  and  specific.  They 
are  various  combinations  of  proximate  principles  familiar 
to  the  chemist,  which  may  conveniently  be  ranged  under 
three  classes  :  The  first  class  of  organic  substances  com- 
prises those  composed  of  principles  having  what  is  called 
a  mineral  origin  ;  these  generally  quit  the  organism  un- 
clianged  as  they  entered  it.  The  second  class  comprises 
those  which  are  crystallizablc,  and  are  formed  in,  the  or- 
ganism, and  generally  quit  it  in  this  state  as  excretions. 
The  third  class  comprises  the  colloids,  i.  e.  substances 
which  are  coagulable  and  not  crystal! izal)le,  and  are 
formed  in  and  decomposed  in  the  organism,  thus  fur- 
nishing the  principles  of  the  second  class.  All  the  prin- 
ciples are  in  a  state  of  solution.      Water  is  the  cliief 


SB  THE  PHYSICAL  BASIS   OF  MIND. 

vehicle  of  the  materials  which  enter  and  the  materials 
which  quit  the  organism;  and  bodies  in  solution  are  sol- 
vents of  others,  so  that  the  water  thus  acquires  new  sol- 
vent properties. 

45 «.  Two  points  must  be  noted  respecting  organic 
substances :  they  are  mostly  combinations  of  higher  mul- 
tiples of  the  elements ;  and  their  combinations  are  not 
definite  in  quantity.  Albumen,  for  example,  has  (accord- 
ing to  one  of  the  many  formulas  which  have  been  given) 
an  elementary  composition  of  21G  atoms  of  Carbon,  169 
of  Hydrogen,  27  of  Nitrogen,  3  of  Sulphur,  and  68  of 
Oxygen ;  whereas  in  its  final  state,  in  which  it  quits  the 
organism  as  Urea,  it  is  composed  of  2  atoms  of  Carbon, 
4  of  Hydrogen,  2  of  Nitrogen,  and  2  of  Oxygen,  all  the 
Sulphur  having  disappeared  in  other  combinations.  In 
like  manner  in  the  organism  Stearin  falls  from  Cn4,  Hhq, 
Oi2,  to  Oxalic  Acid,  which  is  C4,  H2,  Og.  It  is  obvious 
that  the  necessary  modifiability  of  organic  substance  is 
due  to  this  multiplicity  of  its  elementary  parts  and  the 
variety  of  its  molecular  structure. 

455.  Nor  is  the  indefiniteness  of  the  quantitative  com- 
position less  inq:)ortant,  though  seldom  adequately  appre- 
ciated, or  even  suspected.  Eobin  and  Verdeil  *  are  the 
only  writers  I  can  remember  who  have  distinctly  brought 
the  fact  into  prominence.  That  all  inorganic  substances 
are  definite  in  composition,  every  one  knows.  Quick- 
lime, for  example,  may  be  got  from  marble,  limestone, 
oyster-shells,  or  chalk ;  but  however  produced,  it  always 
contains  exactly  250  ounces  of  calcium  to  100  ounces  of 
oxygen ;  just  as  water  is  always  OH2.  Not  so  the  pre- 
eminently vital  substances,  those  which  are  coagulable 
and  not  crystaUizable :  no  precise  formula  will  express 
one  of  these  ;  for  the  same  specific  substance  is  found  to 
vary  from  time  to  time,  and  elementary  analyses  do  not 

*  RoBix  et  Verdeil,  TraiU  dc  Chimic  Anatomiquc,  185-3. 


THE  NATURE   OF  LIFE.  39 

give  uniform  results.  Thus,  if  after  causing  an  acid  to 
combine  with  one  of  these  substances,  we  remove  the 
acid,  we  are  not  certain  of  finding  the  substance  as  it  was 
before  —  as  we  are,  for  example,  after  urea  is  combined 
with  nitric  acid  and  then  decomposed.  The  same  want 
of  definiteness  is  of  course  even  more  apparent  in  the 
combinations  of  these  proximate  principles  into  organized 
substance.  Protoplasm  differs  greatly  in  different  places. 
Epithelial  cells  differ.  Muscular  and  nervous  fibres  are 
never  absolutely  the  same  in  different  regions.  A  striped 
and  unstriped  muscular  fibre,  the  muscular  fibre  of  a 
sphincter  or  of  a  limb,  a  nerve-fibre  in  a  centre,  in  a 
trunk,  or  in  a  gland,  will  present  variations  of  composi- 
tion. The  elastic  fibres  of  the  ligaments  are  larger  in 
the  horse  than  in  man ;  and  in  other  animals  they  are 
smaller.  These  differences  are  sometimes  due  to  the 
constituents,  and  sometimes  to  the  arrangement  of  the 
constituents  ;  the  conversion  of  Albumen  into  Fibrine 
without  elementary  loss  or  addition,  is  a  good  example  of 
the  latter.  That  the  tissues  of  one  man  are  not  absolutely 
the  same  as  the  tissues  of  another,  in  the  sense  in  which 
it  is  true  to  say  that  the  chalk  of  one  hill  is  the  same  as 
that  of  another,  or  as  gold  in  Australia  is  the  same  as  gold 
in  ]\Iexico,  is  apparent  in  their  very  different  reactions 
under  similar  external  conditions :  the  substance  which 
poisons  tlie  one  leaves  the  other  unaffected.  The  man 
wlio  has  once  had  the  small-pox,  or  scarlet  fever,  is  never 
the  same  afterwards,  since  his  organism  has  now  become 
insusceptible  of  these  poisons.  And  Sir  James  Paget  has 
called  attention  to  tlie  striking  lact  revealed  in  disease, 
namely,  that  in  the  same  tissue  —  say  the  bone  or  the 
skin  —  a  morbid  substance  fastens  only  on  certain  small 
portions  leaving  all  tlie  rest  unaltered,  but  fastens  on 
exactly  corresponding  spots  of  the  opposite  sides  of  the 
body ;  so  that  on  both  arms,  or  both  legs,  only  the  corrc- 


40  THE  PHYSICAL  BASIS   OF  MIND. 

sponding  bits  of  tissue  will  be  diseased.  "  Manifestly 
wlien  two  substances  display  different  relations  to  a  third 
their  composition  cannot  be  identical ;  so  that  tliouoh  we 
may  speak  of  all  bone  or  of  all  skin  as  if  it  were  all  alike, 
yet  there  are  differences  of  intimate  composition.  ISTo 
power  of  artificial  chemistry  can  detect  the  difference; 
but  a  morbid  material  can."  *  It  is  to  this  variability  of 
composition  that  we  must  refer  individual  peculiarities, 
and  those  striking  forms  of  variety  known  as  idiosyn- 
crasies, which  cause  some  organisms  to  be  affected  by 
what  seem  inexplicable  influences  —  physical  and  moral. 

In  spite  of  all  these  variations,  however,  there  are  certain 
specific  resemblances  dependent  of  course  on  similarity  of 
composition  and  structure,  so  that  the  muscle  of  a  crusta- 
cean is  classed  beside  the  muscle  of  a  vertebrate,  althouuli 
the  elementary  analysis  of  the  two  yields  different  results. 
Xerve-tissue,  according  to  my  experience,  is  the  most  va- 
riable of  all,  except  the  blood ;  variable  not  only  from 
individual  to  individual,  and  from  genus  to  genus,  but 
even  in  the  same  individual  it  never  contains  the  same 
quantities  of  water,  phosphates,  etc.  Hence  it  is  that  dif- 
ferent nerves  manifest  different  degrees  of  excitability, 
and  the  same  nerve  differs  at  different  times.  Thus  the 
fifth  pair,  in  a  poisoned  animal,  retains  its  excitability  long 
after  the  others  are  paralyzed  ;  and  the  patient  under  chlo- 
roform feels  a  prick  on  the  brow  or  at  the  temples,  when 
insensible  at  any  other  spot.  The  pneumogastric  which 
is  excitable  during  digestion  is  —  in  dogs  at  least  —  in  ex- 
citable when  the  animal  is  fasting. 

46.  The  organic  substances  are  what  analysis  discovers 
in  organized  substances,  but  none  of  them,  not  even  the 
highest,  is  living,  except  as  organized.  Albumen  alone,  or 
Stearin  alone,  is  as  incapable  of  Vitality,  as  Plumbago,  or 
Soda ;  but  all  organic  substances  are  capable  of  playing  a 

*  Paget,  Lectures  on  Surgical  Pathol oriy,  p.  14. 


THE   NATURE   OF   LIFE.  41 

part  in  vital  actions  ;  and  this  part  is  the  more  important 
in  proportion  to  their  greater  molecular  variety.  Organi- 
zation is  a  special  synthesis  of  substances  belonging  to  all 
three  classes ;  and  the  organized  substance,  thus  formed, 
alone  merits  the  epithet  living.  AVe  see  how  organized 
substances,  being  constituted  by  principles  derived  from 
the  inorganic  world,  and  principles  derived  from  the  or- 
ganic world,  have  at  once  a  dependence  on  the  external 
Medium,  and  an  independence  of  it,  which  is  peculiar  to 
living  beings.  An  analogous  dependence  and  independ- 
ence is  noticeable  with  respect  to  the  parts  ;  and  this  is  a 
character  not  found  in  inorganic  compounds.  The  organ- 
ism, even  in  its  simplest  forms,  is  a  structure  of  different 
substances,  each  of  which  is  complex.  While  one  part 
of  a  crystal  is  atomically  and  morphologically  identical 
with  every  otlier,  and  is  the  whole  crystal  "  writ  small," 
one  part  of  an  organism  is  unlike  another,  and  no  jJcirt  is 
like  the  whole.  Hence  the  dependence  of  one  organ  and 
one  tissue  on  another,  and  each  on  all.  Yet,  while  every 
part  is,  so  to  speak,  a  condition  of  existence  of  every 
otlier,  and  the  unity  of  the  organism  is  but  the  expression 
of  this  solidarity,  —  wherever  organized  substance  has 
been  differentiated  into  morphological  elements  (cells,  etc.), 
each  of  these  has  its  own  course  of  evolution  independ- 
ently of  the  others,  —  is  born,  nourished,  developed,  and 
dies. 

47.  The  interdependence  of  nerve  and  muscle  is  seen 
in  this,  that  the  more  the  muscle  is  excited  the  feebler  its 
contractions  become  ;  this  decrease  in  contractility  is  com- 
pen.sated  by  an  increased  excitability  in  its  nerve  ;  8o  that 
while  tlie  muscle  demands  a  more  powerful  stimulus,  the 
nerve  acquires  a  more  energetic  activity.  Ranke's  curious 
and  careful  experiments  seem  to  prove  that  this  depends 
on  the  wearied  muscle  absorliing  more  water,  owing  to  the 
acids  developed  by  its  activity,  and  on  the  nerve  losing 


4J  Tin-:  nivsicAL  basis  of  mind. 

this  water  —  a  nerve  being  always  more  irritable  when  its 
quantity  of  water  diminishes. 

48.  Herein  we  see  illustrated  the  great  law  of  organ- 
ized activity,  that  it  is  a  simultaneity  of  opposite  tenden- 
cies, as  organized  matter  is  a  synthesis  of  compositions 
and  decompositions,  always  tending  towards  equilibrium 
and  disturbance,  storing  up  energy  and  liberating  it.  Un- 
like what  is  observed  in  unorganized  matter,  the  condi- 
tions of  waste  bring  with  them  conditions  of  repair,  and 
thus  —  within  certain  limits  —  every  loss  in  one  direction 
is  compensated  by  gain  in  another.  There  is  a  greater 
flow  of  nutrient  material,  or,  more  properly  speaking,  a 
greater  assimilation  of  it  by  the  tissue,  where  there  has 
been  made  a  greater  opening  for  it  by  previous  disintegra- 
tion. The  alkaline  state  of  the  nutrient  material,  and  the 
acid  state  of  the  material  that  has  been  used,  —  the  alka- 
line state  which  characterizes  repose  and  assimilation,  and 
thfe  acid  state  which  characterizes  activity  and  deassirai- 
lation,  are  but  cases  of  tliis  general  law  ;  on  the  synthesis 
of  these  opposite  tendencies  depends  the  restless  cliange, 
together  with  the  continued  specific  integrity,  of  organized 
matter. 

49.  The  state  of  organization  may  therefore  be  defined 
as  the  molecular  union  of  the  proximate  principles  of  the 
three  classes  in  reciprocal  dissolution.  An  organism  is 
formed  of  matter  thus  organized,  which  exists  in  two 
states  —  the  am.orphous  and  the  fignrcd.  The  amorphous 
substances  are  liquid,  semi-liquid,  and  solid  ;  the  figured 
are  the  cells,  fibres,  and  tubes,  called  "anatomical  ele- 
ments." For  these  I  prefer  the  term  suggested,  I  believe, 
by  Milne  Edwards,  namely,  organitcs,  because  they  are  the 
individual  elements  which  mainly  constitute  the  organs, 
and  are  indeed  by  many  biologists  considered  as  element- 
ary organisms.  These  organites,  which  go  to  form  the 
tissues,  and  by  the  tissues  the  organs,  have  their  specific 


THE   NATURE    OF   LIFE.  43 

form,  volume,  structure,  and  chemical  reactions.  They 
exist  in  textures  or  tissues,  or  separately  (e.  g.  blood  cor- 
puscles), and  are  in  many  respects  like  the  simplest  organ- 
isms known,  such  as  Monads,  Vibrios,  Amoebte,  etc. 

50.  The  simplest  form  of  life  is  not  —  as  commonly 
stated  —  a  cell,  but  a  microscopic  lump  of  jelly-like  sub- 
stance, or  protoplasm,  which  has  been  named  sarcodc 
by  Dujardin,  cytodc  by  Haeckel,  and  (jcrminal  matter  by 
Lionel  Beale.  This  protoplasm,  although  entirely  destitute 
of  texture,  and  consequently  destitute  of  organs,  is  never- 
theless considered  to  be  living,  because  it  manifests  the 
cardinal  phenomena  of  Life:  Assimilation,  Evolution, 
Eeproduction,  Mobility,  and  Decay.  Examples  of  this 
simplest  organism  are  Monads,  Protamoebas,  and  Polytha- 
lamia.*  Few  things  are  more  surprising  than  the  vital 
activity  of  these  organites,  which  puzzle  naturalists  as  to 
whether  they  should  be  called  plants  or  animals.  All 
microscopists  are  familiar  with  the  spectacle  of  a  formless 
lump  of  albuminous  matter  (a  Ehizopod)  putting  forth  a 
process  of  its  body  as  a  temporary  arm  or  leg,  or  else 
slowly  wrapping  itself  round  a  microscopic  plant,  or  mor- 
sel of  animal  substance,  thus  converting  its  whole  body 
into  a  mouth  and  a  stomach ;  but  these  phenomena  are 
surpassed  by  those  described  by  Cienkowski,"!-  who  nar- 
rates how  one  Monad  fastens  on  to  a  plant  and  sucks  the 
chlorophyll  first  from  one  cell  and  then  from  another ; 
another  ]\Ionad,  unable  to  make  a  liole  in  the  cell-wall, 
thrusts  long  processes  of  its  body  into  the  opening  already 
made,  and  drags  out  the  remains  of  the  chloropliyll  left 
there  by  its  predecessor ;  while  a  third  JMonad  leads  a 
l)redatory  life,  falling  upon  other  Monads  that  liave  filled 
themselves  with  food.     Here,  as  he  says,  we  stand  on  the 

*  Comp.  Haeckei,,  in  Suhold  unci  Kollikcr's  Zeitschrift,  1865,  p.  342, 
and  his  GcncrclU  Morpholor/ic,  1866,  I,  13.5,  336. 
t  In  the  Archivfiir  mikros.  Anatomic,  1865,  p.  211. 


•1-i  THE   niYSICAL   BASIS   OF   MIND. 

tliresliold  of  tlmt  dark  region  where  Animal  "Will  begins  ; 
and  yet  there  is  here  only  the  simplest  form  of  organi- 
zation* 

51.  Now  let  our  glance  pass  on  to  the  second  stage  — 
the  Cell.  Here  we  have  a  recognized  differentiation  in 
the  appearance  of  a  nucleus  amid  the  protoplasm.  The 
nucleus  is  chemically  different  from  the  substance  which 
surrounds  it ;  and  although  perhaps  exaggerated  impor- 
tance has  been  attributed  to  this  nucleus,  and  myste- 
rious powers  have  been  ascribed  to  it,  yet  as  an  essential 
constituent  of  the  cell  it  commands  attention.  Indeed, 
according  to  the  most  recent  investigations,  the  defini- 
tion of  a  cell  is  "  a  nucleus  with  surrounding  proto- 
plasm." The  cell-wall,  or  delicate  ^investing  membrane 
—  that  which  makes  the  cell  a  closed  sac  —  is  no  longer 
to  be  regarded  as  a  necessary  constituent,  but  only  as  an 
accessory.-f- 

*  Here  organization  is  the  simplest  form  of  all — molecular  organized 

structure,  which  in  the  higher  forms  becomes  tissue  structure,  and  organ 
structure.  The  word  structure  properly  means  orderly  arrangement  of 
different  materials  ;  and  molecular  structure  refers  to  the  different  prox- 
imate principles  which  constitute  the  organized  substance.  Usuallj', 
however,  the  word  structureless  indicates  the  absence  of  visible  arrange- 
ment of  the  parts  ;  a  cell  has  structure  suice  it  has  nucleus  and  pro- 
toplasm. 

t  In  the  cell-theory  established  by  Scht.eiuen  and  Sciiwanx,  in  1838, 
and  which  has  formed  the  basis  of  modern  histology,  the  cell-wall  was 
endowed  with  an  importance  which  can  no  longer  be  upheld  now  that 
the  existence  of  independent  organisms,  and  of  cells,  without  a  trace  of 
enveloping  membrane  has  been  abundantly  observed.  Cells  without 
walls  were  first  described  by  CosTE  in  the  Comptcs  Rcndus,  1845,  p.  1372. 
They  were  also  described  by  Charles  Eobix  in  1855,  Diet,  de  la  Medicine, 
art.  Cellule.  But  little  notice  was  taken  until  Max  Sciiultze,  in  his 
famous  essay,  Ueher  Muskelkorpcrchen  imd  was  man  eivc  Zelle  zu  ncnnen 
habe,  which  appeared  in  Rcichert  zind  Du  Bois  Rcymond's  ArcMv,  1861,  — 
Bruecke,  in  his  memoir.  Die  Elemcntarorcjanismcn,  1861,  — and  Lionel 
Beale,  in  his  Structure  of  the  Simple  Tissues,  1861,  —  all  about  the  same 
time  began  the  reform  in  the  cell-theory  which  has  effected  a  decisive 
change  in  the  classical  teaching.  Leydig  claims,  and  with  justice,  to 
have  furnished  important  data  in  tliis  direction  {Vovi  Bau  des  thicrischcn 


THE   NATURE   OF   LIFE.  45 

52.  The  cell  may  be  either  an  organism  or  an  organite. 
It  may  lead  an  isolated  life  as  plant  or  animal,  or  it  may 
be  united  with  others  and  lead  a  more  or  less  corporate 
existence ;  but  always,  even  as  an  element  of  a  higher 
organism,  it  preserves  its  own  individuality.  At  first  we 
see  that  the  corporate  union  is  very  sliglit,  merely  the 
contact  of  one  cell  with  another  of  its  own  kind,  as  in 
the  filament  of  a  Conferva.  Eising  higher,  we  see  the 
cell  united  with  others  different  from  it ;  plants  and  ani- 
mals appear,  having  structures  composed  of  masses  of 
various  cells,  liising  still  higher,  we  see  animal  forms 
of  which  the  web  is  woven  out  of  myriads  upon  myr- 
iads of  cells,  with  various  cell-products,  processes,  fibres, 
tubes. 

ORGANISM  AND   MEDIUM. 

53.  But  we  have  only  one  half  of  the  great  problem  of 
life,  when  we  have  the  organism  ;  and  it  is  to  this  half 
that  the  chief  researches  have  been  devoted,  the  other 
falling  into  neglect.  What  is  that  other  ?  The  Medium 
in  which  the  organism  lives.  Every  individual  object, 
organic  or  inorganic,  is  the  product  of  two  factors:  —  first, 
the  relation  of  its  constituent  molecules  to  each  other; 
secondly,  the  relation  of  its  substance  to  all  surrounding 
objects.  Its  properties,  as  an  object  or  an  organism,  are 
tlie  results  of  its  constituent  molecules,  and  of  its  relation 
to  external  conditions.  Organisms  are  the  results  of  a 
peculiar  group  of  forces,  exhibiting  a  peculiar  group  of 

Korpcrx,  18G4,  I.  p.  11).  The  student  interestod  in  this  discussion  should 
consult  M.\x  Sciim/rzK,  Das  Protoplasma  dcr  Rhizopnden  und  dr.r  PJlan- 
zcnzcUcn,  1863;  Hakckel,  Die  Radiol nricn,  18G2;  the  controversial 
papers  by  Riciciiert,  in  his  Arcliiv  (beginning  with  tlie  Report  of  1863\ 
and  Max  Sciiultze,  in  his  Archiv  fUr  mikros.  Amit.,  with  IIenle's  judg- 
ment in  his  Jahrcshcrichfx,  and  Koij.iker's  summing-up  in  tlu;  last  edi- 
tion of  his  Gcioehclehrc.  For  a  full  yet  brief  history  of  tlic  cell-theoiy  see 
Drysdale,  Tlie  Protoplasmic  TJieory  of  Life,  1874,  pp.  96-106. 


4G  THE   niYSICAL   BASIS   OF   MIND. 

phenomena.  Viewing  these  in  the  abstract,  wc  may  say- 
that  there  are  three  regulative  laws  of  life  :  —  (1)  The  Lex 
Formationis — the  so-called  tiisus  formativus,  or  "organiz- 
ing force";  (2).  the  Lex  Adaptationis,  or  adaptive  ten- 
dency ;  (3)  the  Lex  Hcrcditatis,  or  tendency  to  reproduce 
both  the  original  form  and  its  acquired  modifications. 
We  have  always  to  consider  the  organizing  force  in  rela- 
tion to  all  surrounding  forces  —  a  relation  succinctly  ex- 
pressed in  the  word  Ada]jtation.  Just  as  water  is  water 
only  under  a  certain  relation  of  its  constituent  molecules 
to  the  temperature  and  atmospheric  pressure — just  as  it 
passes  into  other  forms  (ice  or  steam)  in  adapting  itself 
to  other  conditions;  so,  likewise,  the  organism  only  pre- 
serves its  individuality  by  the  adjustment  of  its  forces 
with  the  forces  which  environ  it. 

54.  This  relation  of  Organism  and  Medium,  the  most 
fundamental  of  biological  data,  has  had  a  peculiar  for- 
tune :  never  wholly  unrecognized,  for  it  obtrudes  itself 
incessantly  in  the  facts  of  daily  experience,  it  was  very 
late  in  gaining  recognition  as  a  principle  of  supreme  im- 
portance ;  and  is  even  now  often  so  imperfectly  appre- 
hended that  one  school  of  philosophers  indignantly  re- 
jects the  idea  of  the  Organism  and  Medium  being  the 
two  factors  of  which  Life  is  the  product.  Not  only  is 
there  a  school  of  vitalists  maintaining  the  doctrine  of 
Life  as  an  entity  independent  both  of  Organism  and 
Medium,  and  using  these  as  its  instruments  ;  but  tliere 
is  also  a  majority  among  other  biologists,  who  betray  by 
their  arguments  that  they  fail  to  keep  steadily  before 
them  the  fundamental  nature  of  the  relation.  Something 
of  this  is  doubtless  due  to  the  imperfect  conception  they 
have  formed  of  what  constitutes  the  Medium ;  instead  of 
recognizing  in  it  the  sum  of  external  conditions  affecting 
tlie  organism  —  i.  e.  the  sum  of  the  relations  wdiich  the 
organism  maintains  with  external  agencies,  —  they  re- 


THE    NATUKE   OF   LIFE.  47 

strict,  or  enlarge  it,  so  as  to  misapprehend  its  significance 
—  restrict  it  to  only  a  few  of  the  conditions,  such  as 
climate,  soil,  temperature,  etc.,  or  enlarge  it  to  embrace 
a  vast  array  of  conditions  which  stand  in  no  directly 
appreciable  relation  to  the  organism.  Every  one  under- 
stands that  an  organism  is  dependent  on  proper  food,  on 
oxygen,  etc.,  and  will  perish  if  these  are  withheld,  or  be 
affected  by  every  variation  in  such  conditions.  Every 
one  understands  that  an  animal  which  can  devour  or  be 
devoured  by  another,  will  flourish  or  perish  according  to 
the  presence  of  its  prey  or  its  enemy.  But  it  is  often 
forgotten  that  among  external  existences,  all  those  which 
stand  in  no  appreciable  relation  to  the  organism  are  not 
properly  to  be  included  in  its  Medium.  In  consequence 
of  this  oversight  we  frequently  hear  it  urged  as  an  ob- 
jection to  the  Evolution  Hypothesis,  that  manifold  organ- 
isms exist  under  the  same  external  conditions,  and  that 
organisms  persist  unchanged  amid  a  great  variety  of  con- 
ditions. The  objection  is  beside  the  question.  In  the 
general  sum  of  external  forces  there  are  certain  items 
which  are  nearly  related  to  particular  organisms,  and 
constitute  their  Medium ;  those  items  which  are  so  dis- 
tantly related  to  these  organisms  as  to  cause  no  reactions 
in  them,  are,  for  them,  as  if  non-existent.*  Of  the  mani- 
fold vibrations  which  the  ether  is  supposed  to  be  inces- 
santly undergoing,  only  certain  vibrations  affect  the  eye 

*  At  the  time  this  was  written,  I  had  some  fish  ova  in  the  course  of 
development.  Out  of  the  same  mass,  and  in  the  same  vessel,  all  those 
which  were  supported  by  weed  at  a  depth  of  lialf  an  inch  from  the  sur- 
face, lived  and  developed  ;  all  those,  witliout  exception,  that  were  at 
a  depth  of  two  to  four  inches,  i)eri.shed.  In  ordinary  parlance,  .surely, 
nothing  would  be  olyected  to  in  the  phrase,  "these  ova  were  all  in  the 
same  iledium  "  ;  the  water  was  the  same,  tlic  weed  the  same,  the  ves.sel 
the  .same  ;  yet  some  difference  of  temperature  and  carbonic  acid  made 
all  the  difference  between  life  and  death.  Another  curious  fact  was  ol)- 
served  ;  I  removed  eight  of  tliese  ova  with  active  embiyns,  and  placed 
them  in  a  large  watch-glass  containing  a  solution  (one  half  i)er  cent)  of 


48  THE   PHYSICAL   BASIS    OF   MIND. 

as  light ;  these  constitute  the  Medium  of  Siglit ;  the 
others  are  as  if  they  were  not.  Only  certain  vibrations 
of  the  air  afl'ect  the  ear  as  Sound ;  to  all  other  vibrations 
we  are  deaf;  though  ears  of  finer  sensibility  may  detect 
them  and  be  deaf  to  those  which  affect  us. 

55.  "  The  external  conditions  of  existence  "  is  therefore 
the  correct  definition  of  the  Medium.  An  animal  may 
be  surrounded  with  various  foods  and  poisons,  but  if  its 
organism  is  not  directly  affected  by  them  they  cannot  be 
food  or  poison  to  it.  An  animal  may  be  surrounded  with 
carnivorous  rivals,  but  if  it  is  not  adapted  to  serve  them  as 
food,  or  is  too  powerful  to  be  attacked  by  them,  they  only 
indirectly  enter  into  its  Medium,  by  eating  the  food  it 
would  eat.  The  analogy  is  similar  with  anorganisms  and 
their  relation  to  their  media.  Every  physical  or  chemical 
phenomenon  depends  on  the  concurrence  of  definite  condi- 
tions :  namely,  the  substance  which  manifests  the  change, 
and  the  medium  in  which  the  change  is  manifested.  Alter 
the  medium,  solid,  liquid,  or  gaseous,  change  its  thermal 
or  electrical  state,  and  the  phenomenon  is  altered.  But 
although  similar  alterations  in  the  medium  notoriously 
influence  the  organism,  yet,  because  a  great  many  varia- 
tions in  external  conditions  are  unaccompanied  by  appre- 
ciable clianges  in  the  organism,  there  are  biologists  who 
regard  this  as  a  proof  of  Life  being  independent  of  phys- 
ical and  chemical  laws ;  an  error  arising  from  their  not 
recognizing  the  precise  nature  of  organic  conditions. 

56.  To  give  greater  precision  to  the  conception  of  a 
Medium  it  will  be  desirable  to  adopt  the  distinction  much 

bichromate  of  ammonia.  In  this  acid  the  embryos  lived  and  v.-ere  active 
fifty-seven  hours,  although  other  embryos  placed  in  a  similar  watch-glass 
containing  pond-water,  survived  only  forty  hours.  The  non-effect  of  the 
acid  was  probably  due  to  the  non-absorption  which  nullifies  the  effect 
of  certain  virulent  poisons  when  they  are  swallowed  ;  but  why  the  fish 
should  live  longer  in  the  acid  than  in  the  simple  water,  I  do  not  at  all 
comprehend. 


THE   NATURE   OF  LIFE.  49 

insisted  on  by  Claude  Bernard,  namely,  1°,  an  External  or 
Cosmical  Medium,  embracing  the  whole  of  the  circum- 
stances outside  the  organism,  capable  of  directly  affecting 
it,  and  2°,  an  Internal  or  Physiological  Medium,  embra- 
cing the  conditions  inside  the  organism,  and  in  direct  rela- 
tion with  it  —  that  is  to  say,  tlie  plasma  in  which  its  tis- 
sues are  bathed,  by  which  they  are  nourished.  To  these 
add  its  temperature  and  electrical  conditions.  Bernard 
only  includes  the  nutritive  fluid ;  but  inasmuch  as  each 
organism  possesses  a  temperature  and  electrical  state  of 
its  own,  and  these  are  only  indirectly  dependent  on  the 
external  temperature  and  electricity,  and  as  it  is  with  these 
internal  conditions  that  the  organism  is  in  direct  relation, 
I  include  them  with  the  plasma  among  the  constituents  of 
the  Pliysiological  Medium.  Any  change  in  the  External 
Medium,  whether  of  temperature  or  electricity,  of  food  or 
light,  which  does  not  disturb  the  Internal  Medium,  will  of 
course  leave  the  organism  undisturbed;  and  for  the  most 
part  all  the  changes  in  the  External  Medium  which  do 
affect  the  organism,  affect  it  by  first  changing  the  Internal 
Medium.  External  heat  or  cold  raises  or  depresses  the 
internal  temperature  indirectly  by  affecting  the  organic 
processes  on  which  the  internal  temperature  depends. 
We  see  here  the  rationale  of  acclimatization.  Unless  the 
organism  can  adapt  itself  to  the  new  External  JMedium  by 
the  readjustment  of  its  Internal  Medium,  it  perishes. 

57.  We  are  now  enabled  to  furnish  an  answer  to  the 
very  common  objection  respecting  the  apparent  absence  of 
any  direct  influence  of  external  conditions.  Let  the  objec- 
tion first  Ije  stated  in  the  words  of  a  cehibrated  naturalist, 
Agassiz  :  "  It  is  a  fact  which  seems  to  be  entirely  over- 
looked by  those  wlio  assume  an  extensive  influence  of 
l)hysical  causes  upon  tlie  very  existence  of  organized 
l)eings,  that  the  most  diversified  ty])es  of  animals  and 
plants  are  everywhere  found  under  identical  circumstan- 


60  THE  niYsiCAL  basis  of  mind. 

ces.  The  smallest  sheet  of  fresh  Avater,  every  point  of  the 
sea-shore,  every  acre  of  dry  land,  teems  with  a  variety  of 
animals  and  plants.  The  narrower  the  boundaries  which 
are  assigned  as  the  primitive  home  of  all  these  beings, 
the  more  uniform  must  be  the  conditions  under  which 
they  must  be  assumed  to  have  originated ;  so  uniform 
indeed  that  in  the  end  the  inference  would  be  that  the 
same  physical  causes  can  produce  the  most  diversified 
effects." 

Obviously  there  is  a  complete  misstatement  of  the  ar- 
gument here ;  and  the  excess  of  the  misstatement  appears 
in  the  following  passage  :  "  The  action  of  physical  agents 
upon  organized  beings  presupposes  the  very  existence  of 
those  beings."  Who  ever  doulited  it  ?  "  The  simple  fact 
that  there  has  been  a  period  in  the  history  of  our  earth 
when  none  of  these  organized  beings  as  yet  existed,  and 
when,  nevertheless,  the  material  constitution  of  our  globe 
and  the  physical  forces  acting  upon  it  were  essentially 
the  same  as  they  are  now,  shows  that  these  influences 
are  insufficient  to  call  into  existence  any  living  being."* 
Although  most  readers  will  demur  to  the  statement  that 
because  the  material  constitution  of  our  globe  was  "  essen- 
tially the  same"  before  and  after  animal  life  appeared, 
therefore  there  could  have  been  no  special  conditions  de- 
termining the  appearance  of  Life,  the  hypothesis  of  Evo- 
lution entirely  rejects  the  notion  of  organic  forms  having 
been  diversified  by  diversities  in  the  few  physical  condi- 
tions commonly  understood  as  representing  the  Medium. 
Mr.  Darwin  has  the  incomparable.merit  of  having  enlarged 
our  conception  of  the  conditions  of  existence  so  as  to 
embrace  all  the  factors  which  conduce  to  the  result.  In 
his  luminous  principle  of  the  Struggle  for  Existence,  and 
the  Natural  Selection  which  such  a  struggle  determines, 
we  have  the  key  to  most  of  the  problems  presented  by 

*  Agassiz,  Essay  011  Classijication,  1859,  p.  15. 


THE   NATURE   OF  LIFE.  51 

the  diversities  of  organisms  ;  and  the  Law  of  Adapta- 
tion, rightly  conceived,  furnishes  the  key  to  all  organic 
change. 

58.  In  consequence  of  the  defective  precision  with 
which  the  phrase  "  Medium,"  or  its  usual  equivalent 
"  physical  conditions,"  is  employed,  several  biological 
errors  pass  undetected.  Haeckel  *  calls  attention  to  the 
common  mistake  of  supposing  the  organism  to  be  passive 
under  the  influence  of  external  conditions,  whereas  every 
action,  be  it  of  light  or  heat,  of  water  or  food,  necessarily 
calls  forth  a  corresponding  reaction,  which  manifests  itself 
in  a  modification  of  the  nutritive  process.  He  points  out 
the  obverse  of  this  error  in  the  current  notion  that  Habit 
is  solely  due  to  the  spontaneous  action  of  the  organism, 
in  opposition  to  the  influence  of  external  agency,  —  as  if 
every  action  were  not  the  response  to  a  stimulus.  Corre- 
sponding with  the  fluctuations  in  the  Medium  there  must 
necessarily  be  fluctuations  of  Adaptation,  and  I  think  we 
may  safely  assume  that  it  is  only  when  these  fluctuations 
cease  that  the  Adaptation  becomes  Habit.  Tliis  is  the 
interpretation  of  the  phrase  "  Hal)it  is  second  Nature,"  and 
is  very  different  from  the  common  interpretation  which 
attributes  it  to  the  use  or  disuse  of  organs ;  as  if  use  or 
disuse  were  a  spontaneous  uncaused  activity. 

59.  The  organism,  simple  or  complex,  is,  we  have  al- 
ready seen,  built  up  from  materials  originally  derived  from 
the  External  jVIedium,  but  proximately  from  the  Internal 
Medium.  This  statement,  however,  requires  some  quali- 
fication, especially  in  view  of  the  hypotliesis  that  organ- 
ized substance  was  originally  created  such  as  we  now  find 
it,  and  not  evolved  from  inorganic  materials.  Whether 
this  hypotliesis  be  adopted,  or  rejected,  we  have  the  fact 
that  tlic  immense  majority  of  organisms  noiv  existing  — 
if  not  all  —  are  products  of  pre-existing  organisms;  and 

*  Haeckel,  GencrcUe  Morphologic,  II.  211. 


d2  the  physical  basis  of  mind. 

therefore  organized  matter  is  now  mainly,  if  not  solely, 
formed  by  organized  matter. 

"We  take,  therefore,  as  our  point  of  departure,  the  pro- 
toplasm ;  this  is  the  first  of  the  three  terms  of  the  vital 
synthesis  :  Structure,  Aliment,  and  Instrument.  The  eto- 
lution  of  this  is  proximately  dependent  on  the  ^jaZ>i<^w?;i 
afforded  it  in  the  Internal  Medium,  which  is  the  true 
nutrient  material,  and  to  which  what  is  usually  called 
food  stands  in  an  external  relation :  for  between  the  recep- 
tion of  food  and  its  assimilation  by  the  organite,  there  is 
an  indispensable  intermediary  stage,  through  which  matter 
passes  from  the  unorganized  to  the  organized  state.  This 
intermediate  is  now  recognized  in  plants  as  in  animals. 
The  old  belief  that  plants  were  nourished  directhj  from 
the  soil  and  atmosphere  can  no  longer  be  sustained.  The 
process  of  Nutrition  is  alike  in  both  :  in  botli  the  mate- 
rials drawn  from  the  External  Medium  are  formed  into 
proximate  principles  and  organic  substances.  It  is  daily 
becoming  more  and  more  probable  that  the  inorganic 
materials,  water  and  oxygen,  so  freely  entering  into  the  or- 
ganism, never  pass  directly  from  the  External  JNIedium  to 
the  tissues,  but  have  to  pass  through  the  Internal  Medium 
where  they  are  changed,  so  that  the  water  is  no  longer 
free,  but  exists  in  a  fixed  state  which  has  no  analogue  out 
of  the  living  substance.  Only  a  part  of  the  water  can  be 
pressed  out  mechanically;  tlie  rest — that  which  is  already 
incorporated  with  the  other  elements  —  can  only  be  got 
rid  of  in  a  vacuum  and  at  a  high  temperature.  Oxygen, 
also,  comports  itself  differently  in  the  tissue  ;  as  is  proved 
by  the  fact  that  its  physiological  absorption  is  markedly 
diff'erent  from  any  chemical  oxidation  in  a  dead  or  decom- 
posing tissue.*  Be  this  as  it  may,  we  know  that  organic 
substances  have  to  be  unbuilt  and  rebuilt  in  the  organ- 
ism ;  that  the  albumen  of  our  food  never  passes  directly 

*  See  on  this  last  point  Ranke,  Die  Lehenshedingungen  der  Nerven, 
1868,  p.  34. 


THE   NATUKE   OF   LIFE,  53 

into  the  albumen  of  our  tissues  ;  any  more  than  the  milk 
drunk  by  a  nursing  mother  will  pass  into  her  breasts,  and 
increase  her  supply,  except  by  nourishing  her. 

60.  In  the  First  Series  of  these  Problems  the  term 
Bioplasm  was  employed  to  designate  this  organized  part 
of  the  Internal  Medium.  I  was  led  to  adopt  it  as  a  cor- 
responding term  to  that  of  Psychoplasm,  by  which  I 
wished  to  designate  the  sentient  material  of  the  psycho- 
logical medium.  There  can  be  little  doubt  that  the  term 
Bioplasm  was  an  unconscious  reproduction  of  the  title  of 
Dr.  Beale's  work,  which  I  must  have  seen  advertised.  I 
withdraw  it  now  that  I  have  read  Dr.  Beale's  work,  and 
see  that  the  signification  he  attaches  to  the  term  is  almost 
identical  with  Protoplasm.  In  lieu  thereof,  the  term 
Plasmode  (from  iilasma,  anything  formed,  and  odos,  a 
pathway)  may  be  substituted :  it  represents  the  nutrient 
material  on  its  way  to  form  Protoplasm,  whicli  is  forma- 
tive material;  while  the  materials  formed  may  be  termed 
Organites  and  Products :  the  organite  being  the  cell  or 
cell-derivative  (fibre,  tube) ;  the  products  being  the  gaseous 
liquid  and  solid  derivatives  of  vital  processes,  which  are 
secretions  when  they  form  intercellular  substance  or  return 
into  the  plasmode  and  re-enter  the  vital  circle ;  excretions 
when  they  are  rejected,  as  incapable  of  further  assimila- 
tion. The  liver-cell  will  furnish  an  example  of  each  kind 
of  product.  The  bile,  though  containing  principles  service- 
able in  the  chemical  transformations,  is  for  the  most  part 
excreted  ;  but  besides  bile,  the  liver-cell  produces  starchy 
and  saccharine  principles  which  are  true  secretions,  and 
le-enter  tlie  plasmode. 

61.  The  organite  is  thus  composed  of  sap,  sul)stance, 
and  product ;  tlie  organism,  of  plasmode,  tissue,  and  prod- 
uct. A  glance  at  the  vegetable-cell  shows  it  to  be  con- 
stituted by  the  primordial  utricle,  or  proto])lasm,  the 
outermost  layer  of  wliich  is  condensed  into  a  membrane. 


54  THE   PHYSICAL  BASIS   OF   MIND. 

or  cell-wall,  and  the  cavity  thus  enclosed  is  filled  with  sap. 
The  cell-wall  grows  as  the  protoplasm  grows,  and  the  pro- 
toplasm draws  its  material  from  the  plasmode.  A  glance 
at  the  blood,  the  great  reservoir  of  the  river  of  life,  shows 
us  plasmode  in  the  serum,  and  organites  in  the  corpus- 
cles ;  the  one  distinguished  by  sodic  salts,  the  other  by 
potassic  salts.  The  plasmode,  or  serum,  is  in  a  constant 
change  of  composition  and  decomposition,  giving  up  to 
the  various  tissue-organites  and  iutercellular  plasmodes 
the  requisite  materials,  and  receiving  from  organites  and 
plasmodes  the  products  of  their  changes.  The  serum  is 
fed  from  the  food  and  the  tissues  ;  and  it  feeds  the  several 
plasmodes  which  bathe  the  several  tissues.  Passing  into 
the  capillaries,  it  becomes  transformed  as  it  passes  through 
their  walls  into  the  intercellular  spaces,  saturating  the 
acid  products  of  the  cell-activities  with  its  alkalies,  and 
furnishing  the  protoplasms  with  their  needed  materials. 

62.  It  will  be  understood  that,  althougli  in  appearance 
these  stages  are  sharply  defined,  in  reality  they  are  insen- 
sible. But  from  the  analytical  point  of  view  we  may  re- 
gard Nutrition  as  the  ofhce  of  the  plasmode,  and  Evolu- 
tion as  the  office  of  the  protoplasm.  Although  evolution 
or  genesis  of  form  depends  on  assimilation,  it  is  not  a 
necessary  consequence  :  the  plasmode  or  the  protoplasm 
might  preserve  such  perfect  equality  in  the  waste  and 
repair,  such  complete  equilibrium,  as  not  to  undergo  any 
development.  The  ova,  for  example,  which  exist  in  the 
ovaries  at  birth  are  not  all  subsequently  developed  ;  and 
if  with  modern  embryologists  we  conclude  that  there  is 
no  replacement  of  these  by  proliferation  we  shall  in  them 
have  examples  of  organites  remaining  unchanged  through 
a  period  of  fifty  years.*  But  such  an  equilibrium  is  per- 
haps only  possible  in  complete  inactivity. 

*  See  Walpeyer,  art.  Eierstoclc,  in  Stricker's  Handbuch  der  Lchre 
von  den  Gewchcn,  1870,  p.  570.     "  I  found  in  a  foetus,  which,  in  a  case  of 


THE   NATURE   OF   LIFE.  55 

63.  Again,  although  the  office  of  the  plasmode  is  pri- 
marily that  of  forming  protoplasm,  I  think  tliere  is  evidence 
to  suggest  that  it  not  only  does  this,  but  that  some  of  it 
is  used  in  the  direct  development  of  energy,  especially 
heat  and  electricity.  The  various  forms  of  starch  and 
sugar  taken  in  -with  the  food  or  formed  in  the  liver,  cer- 
tainly do  not  as  such  enter  into  protoplasm.  The  same 
with  alcohol. 

64.  It  is  perhaps  in  forgetfulness  of  the  artificial  nature 
of  analytical  distinctions  that  controversies  rage  respect- 
ing what  are  called  intercellular  substances  and  cell-walls. 
Xow  that  the  wall  is  no  longer  regarded  as  an  essential 
constituent  of  the  cell,  but  as  a  secondary  formation,  two 
opinions  are  maintained :  first,  that  it  is  merely  a  concen- 
tration of  the  external  layer  of  protoplasm  ;  secondly, 
that  it  is  a  product  of  secretion  from  the  protoplasm. 
Both  positions  may  be  correct.  Certainly  in  some  cases 
there  is  no  other  appreciable  difference  between  wall  and 
protoplasm  than  that  of  a  greater  consistence  ;  whereas 
in  many  other  cases  there  exists  a  decided  difference  in 
their  chemical  reactions,  showing  a  difference  of  composi- 
tion. Taking  both  orders  of  fact,  we  may  conclude  that 
tlie  cell-wall  is  sometimes  part  of  the  organite,  and  some- 
times product :  a  blood-cell  and  a  cartilage-cell  may  be 
cited  as  examples  of  each.  And  this  argument  applies  to 
the  intercellular  substance  also. 

G5.  The  terms  plasmode  and  protoplasm  are  general, 
and  include  many  species.  There  are  different  plasmodes 
for  the  different  tissues,  so  tliat  we  find  phosphates  of 
soda  in  the  blood-serum,  phosphates  of  potash  in  the 
nerve-plasma,  phosphates  of  magnesia  in  the  rauscle- 
j)lasma,  and  phosphates  of  lime  in  the  bone-plasma ;  hav- 

cxtra-iiterine  pregnancy,  had  lain  thirty  years  in  the  hody  of  its  motlier, 
tlio  .structure  of  tlie  muscles  as  intact  as  if  it  had  been  born  at  its  full 
time."  —  Viuciiow,  Cellular  Palholorjie,  Lect.  XIV. 


56  THE   PHYSICAL   BASIS    OF   MIND. 

ing  severally  to  form  the  specifically  different  protoplasms 
of  these  tissues.  Observe,  moreover,  the  gradations  of 
these  in  respect  of  their  physical  state :  the  blood  being 
the  most  liquid,  the  nerve  a  degree  more  solid,  the  muscle 
still  more  solid,  and  the  bone  almost  entirely  solid  ;  and 
since  solubility  of  material  is  a  necessary  condition  of  the 
chemical  changes,  we  can  understand  how  the  blood,  the 
nerve,  the  muscle,  and  the  bone  represent  degrees  of  vital 
activity :  the  greater  the  instability  of  organized  sub- 
stance, the  more  active  its  molecular  renovation.  Many 
serious  errors  result  from  overlooking  the  specific  differ- 
ences of  protoplasms  ;  among  them  may  be  mentioned  that 
very  common  one  of  asserting  that  the  ovum  of  a  man  is 
not  distinguishable  from  the  ovum  of  any  other  mammal, 
nor  the  ovum  of  a  mammal  from  tliat  of  a  reptile ;  nay, 
we  sometimes  see  it  stated  that  the  protoplasm  from 
which  a  mammal  may  be  developed  is  the  same  as  that 
which  is  the  germ  of  an  oak.  So  long  as  this  simply 
asserts  tliat  we  have  at  present  no  means  of  distinguish- 
ing them  by  any  chemical  or  physical  tests,  there  can  be 
no  objection  raised ;  but  it  is  a  serious  misconception, 
which  any  embryological  investigation  ought  to  rectify, 
to  suppose  that  the  ovum  is  not  specific  from  the 
first. 

66.  Between  the  organites  and  their  plasmodes  tliere 
is  the  necessary  relation,  which  corresponds  with  the  rela- 
tion between  organisms  and  their  mediums.  Once  formed, 
the  organites  are  arranged  side  by  side,  or  end  on  end, 
into  textures  or  tissues,  and  these  are  grouped  into  organs, 
every  organ  being  constituted  by  a  collection  of  tissues, 
as  every  apparatus  is  by  a  collection  of  organs,  and  the 
organism  by  the  federation  of  all  the  parts.  We  have 
more  than  once  insisted  on  the  necessity  of  synthetic  in- 
terpretation to  complete  the  indications  of  analysis  :  which 
means  that  no  account  of  vital  phenomena  is  real  unless 


THE   NATURE   OF  LIFE.  57 

it  takes  in  all  the  co-operant  factors,  both  those  of  the  or- 
gauism  and  the  medium.  Neglect  of  this  canon  vitiates 
Dr.  Beale's  otherwise  remarkable  labors, 

THE  HYPOTHESIS  OF  GERMINAL  MATTER. 

67.  It  may  help  to  elucidate  certain  important  points 
if  I  here  examine  the  hypothesis  which  Dr.  Beale  has 
worked  out  with  such  patient  skill,  but  with  what  seem 
to  me  such  unphysiological  results.  He  deserves,  I  think, 
more  applause  than  has  been  awarded  to  him,  not  only 
for  the  admirable  patience  with  which  lie  has  pursued  the 
idea,  but  also  for  the  striking  definiteness  of  the  idea  it- 
self—  always  a  great  advantage  in  an  hypothesis,  since  it 
gives  precision  to  research.  If  biologists  have  paid  but 
little  attention  to  it,  this  is  no  doubt  due  to  the  theoreti- 
cal, still  more  than  to  the  observational  contradictions  it 
presents.  Histologists  dispute  his  facts,  or  his  interpreta- 
tions ;  while  other  biologists  do  not  see  their  way  in  the 
application  of  his  hypothesis.  Eespecting  all  disputed 
points  of  observation  I  shall  be  silent,  for  I  have  myself 
made  no  systematic  researches  in  this  direction,  such  as 
would  entitle  me  to  form  an  estimate  of  the  evidence. 
But  my  dissent  from  the  hypothesis  is  founded  on  bio- 
logical principles  so  fundamental  that  I  should  be  willing 
to  take  my  stand  entirely  on  the  facts  he  himself  puts 
forward.* 

08.  The  hypothesis  is  that  notliing  in  the  organism  has 
any  claim  to  vitality  except  the  minute  masses  of  proto- 
plasm (by  him  called  bioplasm),  which  in  the  egg  repre- 
sent, he  thinks,  about  the  one-thousandth  part  of  the 
whole  mass,  the  rest  being  lifeless  matter,  namely,  pab- 
ulum, and  formed  material.     This  l)ioplasm  is  the  gcr- 

*  Sec  Bkai.K,  The  Strvdurc  of  Ihc  Simple  Tisanes,  LSCl  ;  tlm  Iiitrod. 
to  his  edition  of  Todd  and  Bowman's  Pliysiolorjicnl  Anatomy,  18CG  ;  and 
Uow  to  Work  u-itk  the  Microscope,  4th  ed.,  18G8  ;  also  Bioplasm,  1872. 


58  THE   PHYSICAL   BASIS   OF   MIND. 

minal  matter  out  of  which,  by  a  process  of  dying,  arise 
the  tissues  and  humors  constituting  the  formed  mate- 
rial —  these,  -with  the  pabulum  which  feeds  the  germinal 
matter,  being  all  dead  material.  The  germinal  matter 
itself,  though  living,  only  lives  because  there  is  tempo- 
rarily associated  with  it  that  Vital  Force  of  which  we 
have  already  spoken  (§  14).  In  virtue  of  this  associa- 
tion, a  particle  of  matter  not  exceeding  the  one  hundred- 
thousandth  of  an  inch  in  diameter  is  said  to  be  alive; 
and,  presumably,  to  contain  within  it  all  those  manifold 
powers  which  the  term  Life  condenses.  The  pabulum 
brought  under  tlie  influence  of  this  Vital  Force  is  trans- 
formed into  germinal  matter  which,  escaping  from  this 
mysterious  influence,  dies  into  tissue.  Muscle-fibres  and 
nerve-fibres  are  thus  not  living  parts,  nor  are  their  ac- 
tions vital.  So  that,  to  be  consistent,  we  must  not  speak 
of  the  organism  as  living,  but  as  a  dead  structure  ^j?'o- 
duccd  by  the  Vital  Force,  and  set  in  action  by  the  aid  of 
scattered  bits  of  germinal  matter.  He  has  not,  1  think, 
stated  whether  each  of  these  bioplasms  lias  its  own  Vital 
Force,  so  that  the  organism  is  the  theatre  of  millions  of 
Vital  Forces ;  or  whether  it  is  one  Vital  Force  which  ani- 
mates the  whole  organic  world  of  plants  and  animals. 
But  nothing  can  be  less  equivocal  than  his  position  re- 
specting the  lifelessness  of  every  jDart  of  the  organism 
except  the  germinal  matter. 

69.  The  germinal  matter  may  be  selected  as  the  pri- 
mary stage  of  the  formed  material,  the  initial  point  of 
growth,  and  thus  stand  for  the  pre-eminently  distinctive 
centre  of  Nutrition ;  but  were  we  to  limit  all  Nutrition 
to  the  germinal  matter,  as  defined  by  Dr.  Beale,  and  deny 
the  co-operation  of  all  the  formed  material,  we  should 
still  not  be  justified  in  restricting  Life  to  simple  Nutri- 
tion. "We  cannot  exclude  such  phenomena  as  those  of 
Sensation  and  Motion,  nor   can   we  assign  these  to  the 


THE   NATURE   OF   LIFE.  59 

germinal  matter*  To  suppose  this,  would  be  equivalent 
to  saying  that  the  steam  which  issues  from  a  teakettle 
is  capable  of  tlie  actions  of  a  locomotive  engine.  The 
steam  from  tlie  kettle  is  like  the  steam  from  the  boiler,  it 
has  molecular  energy,  and  by  this  will  co-operate  in  the 
production  of  mechanical  work,  if  the  mechanism  be  ad- 
justed to  it.  The  molecular  energy  of  the  protoplasm  in 
muscular  fibre  may  be  indispensable  to  the  movements  of 
the  muscles,  but  these,  and  not  the  protoplasmic  move- 
ments alone,  are  muscular  contractions.  An  hypothesis, 
therefore,  which  is  obliged  to  declare  that  muscle-fibre 
and  nerve-fibre  are  not  living,  even  when  active  in  the 
organism,  seems  to  me  defective  at  its  base.  If  we  view 
these  apart  from  the  organism,  they  may,  like  all  the 
other  formed  materials,  be  regarded  as  dead ;  and  no  one 
doubts  that  epidermis,  nail,  horn,  hair,  and  bone  are  dead 
in  this  sense,  that  they  cannot  live  independently,  and 
do  not  reproduce  themselves.  But  so  long  as  even  these 
form  constituents  of  the  living  organism,  they  also  are 
living  (§  42). f  It  is  only  by  a  misconception  of  the  ana- 
lytical artifice  that  so  simple  a  truth  could  have  been 
missed. 

70,  But  this  misconception  meets  us  at  many  a  turn. 
The  Vitalist  hypothesis    of   an   extra-organic   agent  of 

*  "The  phy.sical  property  of  the  tissue  does  not  depend  upon  this  mat- 
ter, nor  is  Us  function  due  to  it."  —  Beale,  Introduction  to  Todd  and 
Bourman,  p.  11.  That  is  to  say,  he  regards  even  contractility  and  neu- 
rility  as  pliysical,  not  vital  facts. 

t  In  turning  over  the  pages  of  a  work  which  was  celebrated  some  half- 
century  ago —  WvDOhvni'a  Grundriss  dcr  Physiolo(jic  —  I  was  interested 
to  find  a  clear  recognition  of  this  hiological  principle  :  "Alio  Thcile  aller 
Organismen,"  he  says,  I.  2.33,  "sie  miigen  noch  so  verscliieden  in  ihrem 
liaii,  in  ihrer  Mischung,  und  in  ihrer  Thiitigkeit  .seyn,  sind  ohno  Aus- 
nahme  als  organisch  mid  niithin  nls  lehend  zu  bctrachf.rn."  In  a  note  he 
adds  that  i)hysiologists  have  considered  certain  solid  parts  —  opidcrniis, 
nail,  hair,  and  hones  — to  be  dead  ;  "  but  all  these  are  organically  devel- 
oped, and  arc  in  direct  connection  with  tlie  other  parts." 


60  TUE  PHYSICAL   BASIS   OF   MIND. 

course  refuses  to  regard  Life  as  the  exj^ression  of  all  the 
co-operant  conditions;  and  even  opponents  of  that  hy- 
pothesis often  fall  into  the  same  error  of  principle,  when 
they  attempt  to  explain  Life  by  localizing  it  in  the  cells ; 
which  is  simply  a  morphological  substitution  for  the  once 
popular  doctrine  that  only  the  vascular  parts  were  organ- 
ized, and  every  part  destitute  of  blood-vessels  was  dead. 
This  idea  seemed  supported  by  the  facts  of  the  most 
higldy  vascular  parts  being  the  most  vital,  and  of  a  par- 
allelism existing  between  the  vital  activity  of  those 
organs  which  when  injected  seemed  almost  entirely  com- 
posed of  blood-vessels,  as  the  liver  and  brain,  and  those 
which  showed  scarcely  a  trace  of  vessels,  as  cartilage  and 
bone ;  it  seemed  supported  also  by  the  appearance  of 
blood-vessels  in  all  new  formations,  and  by  the  idea  of 
the  blood  as  the  nutrient  fluid.  Tlien  came  the  cell-doc- 
trine, and  the  belief  that  the  cell  was  the  really  ultimate 
morphological  element  —  which  may  be  true  —  and  that 
"  here  alone  there  is  any  manifestation  of  life  to  be  found, 
so  that  we  must  not  transfer  the  seat  of  vital  action  any- 
where beyond  the  cell,"  *  —  which  is  very  questionable. 

71.  We  have  already  seen  that  the  cell  is  an  anatomi- 
cal element,  or  organite ;  the  organism  is  but  an  aggre- 
gate of  organites  and  their  plasmodes.  But  Biology, 
which  deals  with  the  organism  as  a  whole,  and  with  func- 
tions which  are  the  resultants  of  all  the  vital  properties, 
must  not  be  restricted  to  any  single  factor,  how^ever  im- 
portant. It  would  assuredly  be  deemed  absurd  to  say 
that  diamond  rings  and  lead-pencils  were  the  same,  be- 
cause the  diamond  and  the  plumbago,  which  are  the 
specific  elements  of  each,  are  both  the  same  chemical 
element,  —  carbon.  The  substance  is  really  different  in 
diamond  and  plumbago,  is  different  in  properties,  and  is, 
in  rings  and  pencils,  united  with  different  substances  into 

*  ViRCHOW,  Die  Cellular  Pathologic,  1860,  Lect.  I. 


THE   NATURE   OF   UFE.  61 

objects  having  very  different  properties.  Whatever  anal- 
ysis may  discover  as  to  the  identities  of  organic  struc- 
tures, we  cannot  explain  a  single  vital  phenomenon  with- 
out taking  into  account  the  three  terms,  Structure,  Ali- 
ment, and  Instrument ;  and  whenever  a  cell  is  said  to  be 
the  seat  of  vital  action,  these  three  terms  must  be  im- 
plied. In  Dr.  Beale's  hypothesis  the  restriction  is  carried 
to  its  extreme ;  not  content  with  the  cell,  he  withdraws 
vital  action  from  the  cell  as  a  whole,  assigning  it  to  the 
protoplasm  and  nucleus  —  cell-contents  and  cell- wall  be- 
ing, in  his  view,  dead.  If  it  be  true  that  the  protoplasm 
is  alone  concerned  in  Nutrition,  yet  Nutrition  is  not  Life. 
Occupied  mainly  with  formative  processes,  it  leaves  other 
indispensable  processes  to  other  parts.  He  instances  the 
removal  of  all  the  tissues  during  the  metamorphoses  of 
insects :  —  "  new  organs  and  textures  are  laid  down  afresh 
and  developed  ah  initio,  instead  of  being  built  up  upon 
those  first  formed."  But  to  show  how  he  restricts  the 
idea  of  Life,  he  adds  :  "  Such  complete  change,  however, 
necessitates  a  state  of  existence  during  which  action  or 
function  remains  in  complete  abeyance."  * 

The  muscles  and  nerves  which  are  instrumental  in  this 
functional  life  are  said  to  be  dead.  It  is  true  that  the 
]nuscle-fibre  does  not  develop  fresh  fibres.  But  it  is 
equally  true  that  tlie  protoplasm  of  muscle  does  not  alone 
execute  muscular  contraction.  Each  has  its  special  ofiice. 
Hence  I  reject  the  idea  that  formed  material  is  dead. 
He  further  says  "  formed  material  may  he  changed,  it  can- 
not change  \i^e\t"  Tiie  antithesis  is  doubly  inexact:  1°, 
nothing  changes  itself,  but  only  yields  to  pressure,  or  re- 
acts on  being  stimulated ;  and  2°,  all  tlie  evidence  at  hand 
is  against  tlie  notion  tliat  the  formed  material  is  not  the 
seat  of  incessant  molecular  change ;  it  is  wasted  and  re- 
paired molecule  by  molecule.     Kolliker  properly  protests 

*  Beale,  Bioplasm,  104. 


62  THE   PHYSICAL   BASIS   OF   MIND. 

against  the  growing  tendency  of  histologists  to  deify 
protoplasm,  and  to  make  it  the  sole  seat  of  vital  changes, 
the  cell-wall  and  cell-products  having  also,  he  says, 
their  physiological  importance.  It  is  manifestly  erro- 
neous to  deny  vital  changes  to  the  red  blood-corpuscles 
on  the  ground  of  their  no  longer  containing  germinal 
matter.* 

72.  The  analytical  view  may  separate  certain  parts  as 
active,  and  other  j^arts  as  passive,  and  thus  regard  the  cells 
as  the  seats  of  vital  activity,  the  intercellular  substance 
as  merely  accessory  and  instrumental ;  but  the  real  or 
synthetical  view  must  recognize  both  parts  as  equally 
indispensable,  equally  vital.  Take  cartilage,  for  instance, 
with  its  enormous  preponderance  of  intercellular  sub- 
stance (formed  material),  and  consider  how  absolutely 
impossible  any  of  its  uses  would  be  were  it  reduced  to 
the  germinal  matter  of  its  corpuscles  !  And  so  of  all  the 
tissues. 

73.  If  formed  material  is  not  to  be  excluded  from  the 
living  parts  of  the  organism,  neither  is  the  plasmode,  out 
of  which  the  germinal  matter  arises,  since  here  we  have 
the  nutritive  changes  in  their  highest  activity ;  and  be- 
cause the  property  of  Nutrition  is  here  most  active,  the 
other  property  of  Development  is  in  abeyance.  Dr.  Beale 
holds  that  pabulum  necessarily  becomes  germinal  matter ; 
but  when  we  come  to  treat  of  Nutrition  it  will  appear 
that  this  is  not  more  true  than  that  Food  necessarily  be- 
comes Tissue :  some  of  it  does  ;  but  much  of  it  is  used 
up  for  heat  and  other  purposes. 

74.  What  is  true  and  important  in  the  distinction  be- 
tween germinal  matter  and  formed  material  is,  that  from 
the  former  onwards  there  is  a  gradual  process  of  devitali- 
zation, the  older  parts  of  every  organite  and  tissue  ap- 
proaching more  and  more  to  the  state  of  inorganic  matter. 

*  KoLLiKER,  Gcwebekkre,  5th  ed.,  1867,  p.  12. 


THE  NATURE  OF  LIFE.  63 

But  to  show  liow  vain  is  the  attempt  to  restrict  Vitality 
to  any  one  out  of  a  complex  of  co-operant  factors,  we 
might  set  up  a  chemical  hypothesis  to  the  effect  that 
Vitality  depends  on  phosphates,  and  with  it  explain  the 
phenomena  quite  as  well  as  with  the  hypothesis  of  ger- 
minal matter.  For  not  only  is  it  found  that  the  jDroduc- 
tive  quality  of  a  soil  dej)ends  on  its  richness  in  phos- 
phates, but,  as  Lehmann  has  shown,  wlierever  cells  and 
fibres  make  their  appearance  phosphates  are  found,  even  in 
the  lowest  organisms,  which,  however,  contain  but  little. 
Phosphates  abound  in  seeds  and  ova,  in  muscles  and  gan- 
glia, and  are  deficient  in  the  woody  parts  of  plants  and 
the  elastic  fibres  of  animals.  The  infant  absorbs  phos- 
phates in  large  quantities  and  excretes  them  in  small 
quantities.  Nervous  activity  is  accompanied  by  the  con- 
sumption of  a  third  more  phosphorus  than  accompanies 
muscular  activity.  Phosphates  are  among  the  most  ener- 
getic of  organic  stimulants.  But  who  would  endow  the 
phosphates  with  A'itality,  on  the  ground  of  their  indispen- 
sable presence  in  all  vital  processes  ? 

75.  Life,  as  we  saw,  is  the  expression  of  the  whole 
organism.  Many  of  the  parts  are  incapable  of  manifest- 
ing any  vital  phenomena  except  in  connection  with  all  the 
rest ;  and  of  those  parts  which  may  be  separated  from  the 
organism  and  continue  to  manifest  some  vital  phenomena, 
none  are  capable  of  manifesting  all.  When  the  connexus 
of  the  parts  is  destroyed  tlie  organism  is  dead.  Long 
after  tliat  cessation  which  we  call  Death,  tliere  are  still 
evidences  of  Vitality  in  some  of  the  parts  :  tlic  heart  will 
continue  to  beat,  the  glands  will  secrete,  tlie  liair  will 
grow,  the  temperature  will  still  be  above  that  of  the  sur- 
rounding medium,  the  muscles  will  be  excitable ;  these 
vital  properties  are  the  activities  of  organized  substances, 
and  so  long  as  tlie  state  of  organization  is  preserved  they 
are  preserved ;  but  the  Life,  which  is  the  synthesis  of  all 


64  THE  PHYSICAL  BASIS   OF  JIIND. 

the  vital  properties,  vanishes  with  the  destruction  of  that 
synthesis. 

76.  May  we  not  generalize  this,  and  say  that  every 
special  form  of  e.xistenee,  organic  or  inorganic,  is  deter- 
mined by  the  synthesis  of  its  elements  ?  Atoms  are 
grouped  into  molecules,  molecules  into  masses,  masses  into 
systems.  Out  of  the  textureless  germinal  membrane  and 
the  yolk,  with  no  additions  from  without  except  oxygen 
and  heat,  are  developed  all  tlie  textures  and  organs  of  the 
chick ;  and  this  chick  weighs  no  more  than  the  egg  out 
of  which  it  was  evolved.  The  development  has  been  a 
succession  of  syntheses  —  epigenesis  upon  epigenesis. 
We  may,  if  we  please,  regard  each  organite,  as  it  appears, 
living  its  separate  life,  and  each  tissue  its  separate  life ; 
but  we  must  not  confound  under  the  same  symbol  modes 
of  existence  so  widely  different  as  the  activities  of  an 
organite,  and  the  activities  of  an  organism  constituted  by 
millions  of  organites. 

77.  If  therefore  we  cannot  restrict  Life  to  the  processes 
of  Nutrition,  Dr.  Beale's  hypothesis,  whatever  value  it 
may  have  as  explaining  histogenesis,  is  quite  unaccepta- 
ble. Neither  Vital  Force  nor  Bioplasm  covers  the  whole 
ground.  For  the  former  there  is  no  better  evidence  than 
our  ignorance  of  tlie  real  synthesis ;  for  the  latter  the  evi- 
dence is  positive  in  its  nature,  but  its  interpretation  is 
questionable.  Dr.  Beale  selects  as  the  germinal  matter 
those  portions  of  tissue  which  are  susceptible  of  being 
deeply  stained  by  the  carmine  solution,  the  formed  mate- 
rial being  only  stained  in  a  faint  degree ;  the  nucleus  and 
nucleolus  are  the  portions  of  germinal  matter  which  are 
most  deepl)'-  stained;  and  hence  he  concludes  that  the 
older  the  matter  the  fainter  will  be  its  coloration.  There 
is  no  dispute  as  to  the  value  of  the  staining  process,  in- 
vented by  Gerlach,  for  the  discrimination  of  chemically 
different  parts  of  a  tissue ;  and  Dr.  Beale  has  made  excel- 


THE   NATURE   OF   LIFE.  65 

lent  use  of  it  in  his  researches*  But  I  altogether  dispute 
tlie  conclusion  that  the  staining  process  reveals  the  parts 
which  are  exclusively  vital ;  and  for  this  reason  :  it  de- 
pends solely  on  the  acid  reaction  of  those  parts ;  and  we 
cannot  divorce  the  acid  from  the  alkaline  agencies,  both 
being  indispensable.  Nay,  it  has  been  proved  that  in  the 
living  animal  no  organized  substance  can  be  stained. 
Lord  Godolphin  Osborne  first  discovered,  in  1856,  that 
the  protoplasm  of  growing  wheat  was  susceptible  of  col- 
oration ;f  but  Gerlach,  in  1858,  found  that  this  never 
took  place  in  the  animal  during  life.  He  kept  tadpoles 
and  intestinal  worms  for  weeks  in  colored  fluids,  without 
a  single  spot  becoming  stained ;  although  no  sooner  did 
these  animals  die  than  the  staining  began.  Nor  even 
when  he  injected  the  colored  fluids  under  the  skin  and 
into  the  stomach,  was  the  slightest  coloration  produced.^ 
To  Gerlach's  testimony  may  be  added  that  of  Stein, 
who,  in  his  magnificent  work  on  Infusoria,  says  that  not 
only  has  no  foreign  substance  ever  been  found  in  the  pro- 
toplasm of  the  Opalina,  but  in  the  Acineta,  and  all  the 
embryos  of  the  higher  Infusoria  known  to  him,  he  has 
been  unable  to  color  the  living  substance.  §  This  resist- 
ance of  the  living  protoplasm  is  surely  a  serious  objection 
to  the  hypothesis  tliat  only  those  parts  of  the  dead  organ- 
ism which  are  stained  were  the  truly  vital  parts.     Ranke 

*  Nevertheless  there  are  some  facts  dii'ectly  contradicting  his  conclu- 
sions. For  examine,  he  considers  the  axis  cylinder  of  the  nerve  to  be 
loinied  material,  and  agrees  with  Max  Schultze  and  others  as  to  its 
lilirillated  structure;  j'et  according  to  Listku  and  Turner,  Gkrlach 
and  Frey,  the  axis  cylinder  is  deeply  stained  by  cannine,  and  in  this  re- 
spect resembles  the  nucleus  of  protof)lasni. 

t  From  the  quite  recent  experiments  M.  Baillon  has  submitted  to  the 
Acadimin  des  Sciences  {I'Ah  February,  1875),  it  appears  that  although  cut 
flowers  absorh)  colored  fluids,  the  roots  when  intact  only  absorb  the  lluid, 
and  reject  the  coloring  matters,  by  a  veritable  dialysis. 

X  Gerlach  cited  by  Ranke,  op.  cit.,  p.  76. 

§  Stein,  Dcr  Organismus  der  Infusionsthicrchcn,  1859,  p.  76. 


G6  THE  PHYSICAL  BASIS   OF  MIND. 

sums  up  the  results  of  bis  experiments  thus :  "  They  all 
show  that  the  living  cell  resists  the  imbibition  of  every 
substance  "which  it  cannot  assimilate.  It  is  precisely  the 
impossibility  of  staining  the  cell  that  proves  this  conclu- 
sively, since  every  particle  of  carmine  absorbed  would 
have  revealed  its  presence." 

It  is  not  to  be  supposed  that  Dr.  Beale  was  unac- 
quainted with  Gerlach's  experiments.  He  lias  at  any  rate 
so  far  qualified  the  statement  of  his  hypothesis  as  to  ad- 
mit that  it  is  only  after  death  that  the  germinal  matter  is 
stained.  "  The  living  matter  "  (he  says,  Hoio  to  Work  vjith 
the  Microscope,  p.  107)  "  possesses  an  acid  reaction,  or  to 
speak  more  coiTectly,  an  acid  reaction  is  always  developed 
immediately  after  its  death."  Xow,  since  this  acid  reac- 
tion only  presents  itself  after  death,  and  it  is  this  which  is 
revealed  by  the  carmine,  we  have  no  right  to  conclude 
that  the  carmine  singles  out  the  vital  parts.  Every  one 
knows  that  the  living  muscle  and  nerve,  when  in  repose, 
present  an  alkaline  or  faintly  neutral  reaction,  and  after 
excitation  this  is  changed  into  an  acid  reaction,  which 
increases  Mith  the  exhaustion  of  the  tissue.  In  strict 
logic,  therefore  —  if  we  could  logically  apply  such  a  test 
—  it  is  the  unstained  parts  that  ought  to  be  called  vital 
But,  in  truth,  alkalinity  and  acidity  are  equally  indispen- 
sable. 

78.  The  main  object  of  my  bringing  this  question  for- 
ward was  to  illustrate  the  danger  of  being  misled  by 
analysis  :  a  danger  we  shall  see  to  be  very  serious  in  psy- 
chological inquiries.  The  aid  derived  from  analysis  need 
never  be  undervalued  ;  all  that  we  have  to  bear  in  mind 
is  that  it  is  only  a  logical  artifice,  and  that  our  real  expla- 
nation must  always  be  synthetic.  Because  of  the  ten- 
dency to  rely  on  analysis  there  has  been  an  imperfect  dis- 
crimination of  the  profound  difference  between 


THE   NATUKE   OF  LIFE.  67 


ORGANISMS   AND  MACHINES  ; 

and  while  on  the  one  hand  the  legitimate  striving  of  the 
biologist  to  display  the  mechanism  of  organic  actions  has 
been  denounced  by  a  certain  school  as  Materialism  and  a 
hateful  attempt  to  "  rob  Life  of  its  mystery,"  there  has 
been  on  the  other  hand  a  misconception  of  this  mechan- 
ism, as  if  its  dependent  actions  were  of  the  nature  of 
machines,  that  is  to  say,  as  if  organized  mechanisms  were 
strictly  comparable  with  machines  constructed  of  inor- 
ganic parts.  No  doubt  the  laws  of  Mechanics  are  the 
same  in  both,  for  these  are  abstract  laws  which  take  no 
account  of  concrete  differences.  But  when  elaborate 
parallels  are  drawn  up  between  steam-engines  and  ani- 
mal organisms,  the  coal  consumed  in  the  one  likened  to 
the  food  in  the  other,  and  the  force  evolved  in  the  com- 
liustion  in  both  being  the  same,  there  is  a  complete  oblit- 
eration of  all  that  specially  distinguishes  vital  activity. 

79.  Between  an  organism  and  a  machine  there  is  the 
superficial  resemblance  that  both  have  a  complex  struc- 
ture, and  are  constructed  of  different  and  dependent  parts. 
But  underneath  this  resemblance  there  is  a  radical  diver- 
sity.* The  arrangement  of  parts  in  the  organism  is  more 
than  Q,  jnxtajwdtion,  it  is  a  solid ar it y,^x\?,\x\gixom.  tlie  fact 
of  their  being  all  differentiations  from  a  common  sub- 
stance which  is  a  special  combination  of  the  three  classes 
of  proximate  principles.  Tlius  they  are  not  parts  which 
have  been  put  together,  but  which  have  been  evolved,  each 
out  of  a  pre-existing  part,  and  each  co-o])erating  in  the 
very  existence  of  the  otlier.  The  machine  is  made  of 
independent  and  primarily  unrelated  parts  ;  its  integrity 
depends  on  tlie  continued  preservation  of  the  substance 

*  Staiil  had  a  profound  conviction  of  the  radical  difference,  though 
lie  was  not  able  to  point  out  the  conditions  involved.  See  his  Disquisi- 
Ho  de  mcc/ianismi  el  onjanismi  vera  divcrsitate. 


G8  THE   PHYSICAL   BASIS   OF   MIND. 

of  each  part;  waste  is  here  destruction.  The  organism 
is  constituted  by  interdependent  and  primarily  related 
parts ;  its  integrity  depends  on  the  continued  destruction 
and  renovation  of  their  substance  ;  waste  is  a  condition  of 
vitality.  The  actions  of  the  machine  are  s/f&ordinated ; 
the  actions  of  an  organism  are  co-ordinated.  The  lever 
moves  a  wheel,  and  the  wheel  in  moving  liberates  a 
spring,  each  transmitting  a  communicated  impulse,  but 
otherwise  each  acts  independently  —  no  slight  modifica- 
tion in  the  structure  or  movement  of  the  wheel  will 
modify  the  structure  or  the  movements  of  the  lever,  no 
alteration  in  the  tension  of  the  spring  will  affect  the 
structure  of  the  wheel.  But  in  the  organism  all  are  parts 
of  one  sympathetic  whole ;  each  reacts  on  each ;  each  is 
altered  by  the  other.  Not  a  nerve  is  stimulated,  nor  a 
muscle  moved,  but  the  entire  organism  is  affected.  A 
condensation  here  is  the  cause  of  a  greater  imbibition 
there.  The  injection  of  salt  or  sugar  under  the  skin  of 
the  frog's  leg  will  produce  cataract  in  its  eye.  The  activ- 
ity of  a  secreting  cell  in  the  ovary,  or  liver,  alters  the 
condition  of  the  byain  ;  the  activity  of  the  brain  will  check 
the  secretion  of  a  gland,  or  relax  the  sphincters  of  the 
bladder.  When  we  observe  the  growth  of  horns,  or  the 
appearance  of  the  beard,  concomitant  with  the  secretion 
of  spermatic  cells  —  and  especially  when  we  observe 
with  these  a  surprising  cliange  in  the  physical  and  moral 
capabilities  and  tendencies  of  the  organism  —  we  under- 
stand how  the  remotest  parts  of  this  mechanism  are 
bound  together  by  one  subtle  yet  all-powerful  tie.  Noth- 
ing of  this  is  visible  in  a  machine.  In  a  machine  the 
material  is  so  far  of  secondary  importance  that  it  may  be 
replaced  by  materials  of  various  kinds :  a  pulley  may  be 
worked  with  a  hempen  cord,  a  silken  cord,  or  an  iron 
chain  ;  a  wheel  may  be  wood,  iron,  copper,  brass,  or  steel ; 
the  actions  will  in  each  case  be  similar.      Not  so  the 


THE   NATURE  OF   LIFE.  69 

organic  meclianism :  the  slightest  variation,  either  in  com- 
position or  intimate  structure,  will  affect,  and  may  frus- 
trate the  organic  activity.  It  is  only  in  the  skeleton  that 
the  specific  character  of  the  materials  may  be  changed ; 
and  here  only  in  the  substitution  of  one  pliosphate  for 
another  in  the  solid  masonry.* 

80.  Another  marked  characteristic  of  the  organism  is 
that  it  has  a  connexus  of  actions,  the  simultaneous  effect 
of  a  continuous  evolution,  appearing  in  stages  and  ages. 
And  in  the  animal  organism  there  is  a  consensus  as  well 
as  a  connexus,  through  which  there  is  evolution  of  Mind ; 
and  in  the  Social  Organism  an  evolution  of  Civilization. 
This  consensus  forms  an  intermediate  stage  through 
which  the  animal  actions  are  sensitive  as  well  as  nutri- 
tive, and  the  nutritive  are  regulated  by  the  sensitive. 
It  is  obvious  that  nothing  like  this  is  to  be  found  in  a 
machine ;  and  we  conclude,  therefore,  that  any  view  of 
the  organism  which  regards  its  mechanism  without  tak- 
ing in  these  cardinal  characteristics  must  be  radically 
defective.  We  no  more  deny  the  existence  of  mechani- 
cal phenomena  in  denying  that  the  organism  is  like  a 
machine,  tlian  we  deny  the  existence  of  chemical  phe- 
nomena in  denying  that  Vitality  is  chemical. 

*  M.  Feunaxd  Papillon  ha.s  sliown  that  animals  may  bo  foci  with  food 
deprived  of  phosphates  of  lime  if  its  place  is  supplied  with  magnesia, 
strontia,  or  alumina  ;  they  make  their  hones  out  of  these  as  out  of  lime. 
Bat  no  such  substitution  is  possible  in  muscle,  nerve,  or  gland  ;  we  can- 
not replace  the  phosphate  of  magnesia  in  muscles  by  the  phosphate  of 
iron,  lime,  or  potash,  as  we  can  replace  the  iron  of  a  wheel  by  steel,  cop- 
licr,  or  brass. 


70  THE  PHYSICAL  BASIS   OF  MIND. 


CHAPTEE    IV. 

THE   PKOPERTIES   AND   FUNCTIONS. 

81.  The  terms  Property  and  Function  are  not  always 
used  with  desirable  precision.  There  is,  however,  a 
marked  distinction  between  the  property  which  charac- 
terizes a  tissue  in  whatever  organ  the  tissue  may  be 
found,  and  the  function  which  is  exhibited  by  an  organ 
composed  of  several  tissues.  We  ought  never  to  speak 
of  a  function  unless  we  imply  the  existence  of  a  correla- 
tive organ ;  and  it  is  therefore  incorrect  to  speak  of  the 
function  of  Nutrition,  since  all  the  tissues  nourish  them- 
selves; but  we  may  speak  of  certain  organs  as  special 
instruments  in  facilitating  Nutrition.  Thus  also  with 
respiration,  usually,  but  not  accurately,  spoken  of  as  the 
function  of  the  lungs ;  the  lungs  being  simply  the  most 
effective  of  the  instruments  by  which  the  interchange  of 
gases  (which  also  takes  place  in  every  tissue)  is  facili- 
tated. If  by  Ptespiration  we  mean  Breathing,  then,  in- 
deed, Eespiration  is  the  function  of  the  lungs ;  if  we 
mean  the  absorption  of  oxygen  and  the  exhalation  of 
carbonic  acid,  Piespiration  is  a  general  property  of  vital 
tissue.  A  fragment  of  muscle  removed  from  the  body 
respires,  so  long  as  its  organization  is  intact ;  but  it  does 
not  hreathe  —  it  has  no  accessoiy  instruments,  nor  does 
it  need  them.  The  co-operation  of  nerve  centres,  dia- 
phragm, ribs,  circulating  system,  etc.,  necessary  in  the 
complex  organism  to  bring  the  due  amount  of  oxygen  to 
the  tissues,  and  convey  away  the  carbonic  acid,  is  here 


THE    NATURE    OF   LIFE.  71 

needless.  In  the  ascending  animal  series  we  find  this 
necessity  growing  with  the  complexity  of  the  organism. 
The  whole  skin  respires  in  the  amphibia,  and  to  some 
extent  in  man  also :  a  frog  will  live  for  ten  or  fourteen 
days  after  extirpation  of  its  lungs,  the  skin  respiring- 
sufficiently  to  keep  up  a  feeble  vitality.  But  the  skin 
does  not  suffice;  and,  very  early,  certain 'portions  are 
specialized  into  organs  (at  first  in  the  shape  of  external 
gills,  and  finally  as  internal  lungs),  for  the  more  energetic, 
because  more  specialized,  performance  of  this  office.  In 
the  simpler  organisms  the  blood  is  easily  reached  by  the 
air;  therefore  no  instrument  is  needed.  In  primitive 
societies  the  transport  of  goods  is  effected  by  men  and 
women  carrying  them ;  in  civilized  societies  by  the  aid 
of  horses  and  camels,  and  wagons  drawn  by  oxen ;  till 
finally  these  are  insufficient,  and  railways  are  created, 
whose  power  of  transport  transcends  the  earlier  methods, 
as  the  breathing  of  a  mammal  transcends  the  respiration 
of  a  mollusc.  Breathing  is  the  special  function  of  an 
organ  —  the  lungs  (or  more  strictly,  the  thoracic  appara- 
tus) —  as  Eailway  Transport  is  a  special  social  function. 
Although  each  of  the  tissues  forming  this  organ  can,  and 
does,  exhale  carbonic  acid  and  absorb  oxygen  —  and  each 
of  the  railway  servants  can,  and  does,  transport  objects 
to  and  from  the  locomotive  —  yet  the  main  work  is 
thrown  upon  the  special  apparatus. 

82.  What  is  meant  by  properties  of  tissue  and  func- 
tions of  organs  may  be  thus  illustrated.  Let  us  suppose 
ourselves  investigating  the  structure  of  a  sliip.  Wc  find 
it  composed  of  various  materials  —  wood,  iron,  copper, 
hemp,  canvas,  etc. ;  and  these  under  various  configura- 
tions are  formed  into  particular  parts  serving  particular 
purposes,  such  as  deck,  masts,  anchor,  windlass,  chains, 
ropes,  sails,  etc.  In  all  these  parts  the  materials  preserve 
their  properties ;   and  wherever  wood   or   iron   may  be 


72  THE   PHYSICAL  BASIS   OF  MIND. 

placed,  whatever  purpose  the  part  may  serve,  the  prop- 
erties of  wood  and  iron  are  unaffected ;  and  it  is  through 
a  combination  of  these  properties  that  the  part  is  effec- 
tive ;  while  through  the  connection  of  one  part  with 
another  the  purpose  becomes  realized.  The  purposes  to 
which  masts,  ropes,  or  sails  are  subservient  may  be  called 
their  functions ;  and  these  of  course  only  exist,  as  such, 
in  the  ship.  It  is  the  same  with  the  organism.  We 
find  it  composed  of  various  Tissues,  and  these  are  com- 
bined into  various  Organs  or  Instruments.*  The  prop- 
erties of  Tissues  remain  the  same,  no  matter  into  what 
Organs  they  may  be  combined ;  they  preserve  and  exert 
their  physical,  chemical,  and  vital  properties,  as  wood 
and  iron  preserve  their  properties.  Each  Tissue  has  its 
characteristic  quality;  and  the  Organ  which  is  constructed 
out  of  a  combination  of  several  Tissues,  more  or  less 
modified,  is  effective  solely  in  virtue  of  these  properties,  -f- 
while  the  Function  of  that  organ  comes  into  play  through 
its  combination  with  other  organs.  For  example,  mus- 
cular tissue  has  a  vital  property  which  is  characteristic 
of  it.  Contractility;  and  muscles  are  organs  constituted 
by  tliis  tissue  and  several  others ;  :j:  such  organs  have  the 

*  Anatomy  resolves  the  Tissues  into  Organites  (cells,  fibres,  tubes)  ; 
here  its  province  ends,  and  that  of  Chemistiy  begins  by  pointing  out 
the  molecular  composition  of  the  Organites. 

t  This  luminous  conception,  though  vaguely  seized  by  Pixel,  was 
first  definitely  wrought  out  by  Bichat.  See  his  Eecherches  sur  la  Vie 
c.tla  Mort  —  and  especially  his  Jnatomie  Generale,  1812,  I.  p.  Ixx.  It 
was  one  of  the  most  germinal  conceptions  of  modern  times. 

X  Just  as  there  go  other  materials  besides  canvas  to  make  a  sail,  and 
others  besides  iron  to  make  a  windlass,  so  there  go  other  tissues  besides 
the  muscular  to  form  a  muscle  —  there  is  the  membranous  envelope,  the 
nerve,  the  blood-vessels,  the  lymphatics,  the  tendon,  and  the  fat.  Even 
in  Contraction  there  is  another  property  involved  besides  the  Contrac- 
tility of  the  muscular  element,  namely,  the  Elasticity  of  the  fibrous 
wall  of  the  muscular  tube  ;  but  Contractility  is  the  dominant  property, 
and  determines  the  speciality  of  the  function. 


THE    NATURE   OF   LIFE.  73 

general  function  of  Contraction,  but  whether  this  shall 
be  specially  manifested  in  the  beating  of  the  heart,  the 
winking  of  the  eyelid,  the  movement  of  the  chest,  or  tlie 
varied  movements  of  the  limbs,  will  depend  on  the  ana- 
tomical connections.  The  reader  unfamiliar  with  Biology 
is  requested  to  pay  very  particular  attention  to  this 
point ;  he  will  find  many  obscurities  dissipated  if  he  once 
lays  hold  of  the  "  principal  connections." 

82«.  Although  Bichat's  conception  was  of  great  value, 
it  was  not  sufficiently  disengaged  from  the  metaphysical 
mode  of  viewing  biological  phenomena.  Both  he  and 
his  disciples  will  be  found  treating  Properties  as  entities, 
and  invoking  them  as  causes  of  the  phenomena  instead 
of  recognizing  them  simply  as  abstract  expressions  of  tlie 
phenomena.  Eeaders  of  my  First  Series  will  remember 
how  often  I  have  had  occasion  to  point  out  this  common 
error:  men  having  baptized  observed  facts  with  a  com- 
prehensive name,  forget  the  process  of  baptism,  and  sup- 
pose the  name  to  represent  a  mysterious  agency.  The 
fact  that  gases  combine  is  expressed  in  the  terra  affinity ; 
and  then  Affinity  is  understood  to  be  the  cause  of  the 
combinations.  The  fact  that  bodies  tend  towards  each 
other  is  called  their  gravitation,  and  Gravitation  is  then 
said  to  cause  the  tendency.  The  doctrine  of  vital  prop- 
erties has  been  thus  misunderstood.  While  no  one  im- 
agines that  he  can  operate  on  affinity  otherwise  than  by 
operating  on  the  known  conditions  under  which  gases 
combine,  many  a  biologist  and  physician  speaks  as  if  he 
could  operate  on  the  Irritability  of  a  tissue,  or  the  Co- 
ordination of  muscles,  by  direct  action  on  these  abstrac- 
tions. 

Let  it  be  tlierefore  once  for  all  expressly  stated  that  by 
the  property  of  a  tissue  is  simply  meant  tlie  constant  mode 
of  reaction  of  that  tissue  under  definite  conditions.  Tlie 
property  is  not  a  cause,  otherwise  than  the  conditions  it 


7-i  TUH   PHYSICAL   BASIS   OF   MIND. 

expresses  are  a  cause.  And  these  conditions  are  first 
those  of  the  organized  structure  itself,  and  secondly  those 
of  the  medium  in  whicli  it  lives.  Oxygen  unites  with 
Hydrogen  to  form  water,  but  only  under  certain  pressures  ; 
so  likewise  muscles  manifest  Contractility  on  being  stim- 
ulated (that  is  tlieir  mode  of  reaction),  but  only  under 
certain  degrees  of  temperature,  humidity,  and  a  certain 
chemical  composition  of  the  plasmode.  The  property  is 
so  truly  an  expression  of  the  co-operant  conditions,  that 
it  is  found  to  vary  with  those  conditions,  and  to  vanish 
when  they  vary  beyond  a  certain  limit. 

An  attempt  has  been  made  to  restrict  the  notion  of  a 
property  to  an  ultimate  fact.  Whatever  is  not  reducible 
to  known  conditions  is  to  be  accepted  as  a  property. 
Combustion,  for  example,  is  reducible  to  the  molecular 
combination  of  oxygen  and  some  other  gas ;  but  this 
combination  itself  is  not  reducible,  and  it  is  therefore  chris- 
tened affinity.  I  cannot  accept  this  view.  Admitting 
our  inability  to  say  ivhy  gases  combine  under  certain  con- 
ditions (and  in  this  sense  all  facts  are  inexplicable  and 
ultimate,  unless  we  take  the  lioio  as  ample  explanation  of 
the  loliy),  I  must  still  say  that  since  affinity  itself  depends 
on  the  co-operation  of  known  conditions,  it  is  not  less  ex- 
plicable than  combustion.  But  the  point  is  unimportant : 
what  we  have  liere  to  settle  is  the  meaning  of  a  property 
of  tissue,  —  and  that  is  the  mode  of  reaction  which  tliat 
tissue  manifests  under  constant  conditions,  internal  and 
external 

83.  The  evolution  of  Life  is  the  evolution  of  special 
properties  and  functions  from  general  properties  and  func- 
tions. The  organism  rises  in  power  as  it  ramifies  into 
variety.  Out  of  a  seemingly  structureless  germinal  mem- 
brane, by  successive  differentiations  certain  portions  are 
set  apart  for  tlie  dominant,  or  exclusive,  performance  of 
certain  processes;  just  as  in  the  social  organism  there  is 


THE   NATURE   OF   LIFE.  75 

a  setting  apart  of  certain  classes  of  men  for  the  domi- 
nant or  exclusive  performance  of  offices,  which  by  their 
co-operation  constitute  Society.  The  soldier  fights,  but 
ceases  to  build  or  reap,  weave  or  teach ;  the  mason  builds  ; 
the  agriculturist  sows  and  reaps ;  the  priest  and  thinker 
teach  ;  the  statesman  governs.  In  simple  societies  each 
does  all,  or  nearly  all ;  but  the  social  life  thus  manifested 
is  markedly  inferior  to  the  energetic  life  of  a  complex 
society.  So  with  organisms.  An  amoeba  manifests  the 
general  properties  of  Nutrition,  Eeproduction,  Sensibility, 
and  Movement.  But  it  has  no  special  organs,  conse- 
quently no  special  functions.  The  polype  has  a  certain 
rudimentary  specialization  of  parts  :  it  has  a  simple  ali- 
mentary cavity,  and  prehensile  tentacles ;  and  although 
by  these  it  can  seize  and  digest  its  prey,  it  can  only  do  so 
in  a  limited  w^ay  —  all  the  manifold  varieties  and  power 
of  prehension  and  digestion  observed  in  more  complex 
organisms  are  impossible  with  such  organs  as  the  polype 
possesses. 

84.  Differences  of  structure  and  connection  necessarily 
bring  .about  corresponding  differences  in  Function,  since 
Function  is  the  directed  energy  of  the  Properties  of  tissues. 
One  organ  will  differ  from  another  in  structure,  as  the 
liver  from  the  pancreas,  or  the  kidney  from  the  spleen  ; 
or  one  organ  may  closely  resemble  another  but  differ  from 
it  only  in  co7inections,  as  a  sensory  and  a  motor  nerve,  or  an 
extensor  and  a  flexor  muscle.  We  must  therefore  always 
l)ear  both  points  in  mind.  Every  modification,  structural 
or  connectional,  is  translated  by  a  corresponding  modifica- 
tion in  the  office.  The  hand  and  the  foot  sliow  this  well. 
The  tissues  are  the  saYne  in  both,  the  properties  are  the 
same,  and  botli  have  the  same  general  function  of  Pre- 
hension ;  but  their  morphological  differences  carry  corre- 
sponding differences  in  tlieir  uses. 

Suppose  we  have  a  galvanic  battery,  we  know  that  its 


76  THE  PHYSICAL   BASIS   OF   MIND. 

electric  force  may  be  variously  applied.  Two  pieces  of 
charcoal  lixed  to  the  ends  of  its  conducting  wires  give  us 
the  electric  light ;  replacing  the  charcoal  by  a  telegraphic 
apparatus  we  can  transmit  a  message  from  one  continent 
to  the  other  ;  the  wires  dipped  in  a  solution  effect  a  chem- 
ical decomposition,  dipped  into  a  mixture  of  gases  they 
effect  a  chemical  composition.  In  these,  and  many  other 
applications,  the  property  of  the  battery  is  constant ;  but 
the  functions  it  subserves  have  varied  with  the  varying 
co-operants.  So  with  the  properties  of  tissue.*  Not  only 
have  we  to  bear  in  mind  the  organic  connections  of  the 
tissues,  but  also  the  relation  of  the  organs  to  their  media. 
Swimming  and  Walking,  for  example,  are  both  functions 
of  the  locomotive  apparatus,  but  they  are  specially  differ- 
enced by  the  media  in  which  the  animal  moves. 

85.  The  properties  of  tissues  are  their  peculiar  modes 
of  reaction,  and  each  tissue  has  its  dominant  characteris- 
tic, such  as  the  Contractility  of  the  muscle,  and  the  Neur- 
ility  of  the  nerve.  But  there  has  of  late  years  sprung  up 
a  misleading  conception,  partly  a  consequence  of  the  cell- 
theory,  and  partly  of  the  almost  ine\itable  tendency  of 
analysis  to  disregard  whatever  elements  it  provisionally 
sets  aside  ;  this  conception  is  the  removal  of  the  property 
from  its  tissue,  and  the  localization  of  it  in  one  of  the 
organites  —  cell  or  fibre.  This  has  been  conspicuously 
mischievous  in  the  case  of  the  nerve-cell,  which  has  been 
endowed  with  mysterious  powers,  and  may  be  said  to 
have  usurped  the  place  of  nerve-tissue.  I  shall  have  to 
speak  of  this  in  the  next  problem.  Here  I  only  warn  the 
student  against  the  common  error.     The  properties  of  a 

*  "L'element  musculaire  peut  etre  annexe  a  une  foule  de  niecanismes 
(livers  ;  tantot  a  nn  os,  tantot  a  un  intestin,  tantot  a  line  vessie,  tantSt 
a  un  vaisseau,  tantot  a  un  conduit  excreteur,  tantot  enfin  a  dcs  appareils 
tout  a  fait  speciaux  acertainesespeces  d'animaux."  —  Claude  Bernard, 
Eapport  sur  Ics  Progrks  de  la  Physiologie  g&iierale,  1867,  p.  38. 


THE   NATURE   OF   LIFE.  77 

tissue  depend  on  the  structure  and  composition  of  that 
tissue,  together  with  its  plasmode  and  products  ;  they 
vary  as  these  vary.  To  select  any  one  element  in  this 
complex,  and  ascribe  the  reaction  of  the  tissue  to  that,  is 
only  permissible  as  a  shorthand  expression. 

86.  What  has  just  been  expounded  may  be  condensed 
in  the  following  l;)iological  law :  — 

Identity  of  tissue  everywhere  iinplies  identity  of  property  ; 
and  similarity  of  tissue  corresponding  similarity  of  prop- 
erty. Identity  of  organic  connection  everywhere  implies 
identity  of  function ;  and  similarity  of  organic  connection 
sim  ilarity  of  function. 

87.  This  law,  first  formulated  by  me  in  1859,  and  then 
applied  to  the  interpretation  of  nervous  functions,  was  so 
little  understood  that  for  the  most  part  it  met  with  either 
decided  denial  or  silent  neglect ;  no  doubt  because  of  the 
general  disinclination  to  admit  that  tlie  properties  and 
functions  of  the  spinal  cord  could  ha  similar  to  those  of 
the  brain,  in  correspondence  with  the  similarity  of  their 
tissues  and  organic  connections.  Even  Professor  Vulpian, 
who  adopted  it,  as  well  as  my  principal  interpretations, 
hesitated,  and  relapsed  into  the  ortliodox  view  in  assign- 
ing three  different  properties  to  one  and  the  same  tissue 
in  cord,  medulla  oblongata,  aud  cerebrum.*  In  the  course 
of  our  inquiries  we  shall  so  frequently  liave  to  invoke  this 
law  til  at  I  earnestly  beg  the  reader  to  meditate  upon  it, 
and  ask  himself  upon  what  other  grounds,  save  those  of 
structure   and   connection,  the  properties  and  functions 

*  Vulpian,  Lccons  sur  la  PIn/sio/ogic  du  Syslhnc  Ncrvcux,  18G6,  p.  .')81 . 
In  a  work  just  published  I  find  M.  Luvs  hesitating  at  the  consistent 
application  of  this  law.  After  pointing  out  the  identity  of  the  tissue  in 
cerebnim  and  spinal  cord,  he  is  only  prepared  to  say  that  we  cannot  deny 
that  there  is  no  irnpossibilUy  in  admitting  physiological  equivalence 
where  there  is  morphological  equivalence.  —  LuYS,  Actions  Reflexes  du 
Ccrveau,  1874,  p.  14. 


78  THE  rnYsicAL  basis  of  mind. 

can  possibly  rest  ?  If  on  no  other,  then  similarity  in 
structure  and  connection  by  logical  necessity  involves 
similarity  in  property  and  function. 

DOES  THE  FUNCTION  DETERMINE  THE  ORGAN  ? 

88.  Closely  connected  with  this  law,  which  simply 
formulates  the  self-evident  principle  that  every  action  is 
rigorously  deter nvmed  hy  the  nature  of  the  aycnt,  and  the 
conditions  under  which  the  act  takes  place,  is  the  surpris- 
ing question  whether  functions  are  dependent  upon  organs, 
or  organs  dependent  on  functions  ?  —  a  question  which 
sometimes  takes  this  shape :  Is  Life  the  result  of  organ- 
ization, or  is  organization  the  result  of  Life  ? 

The  vitalist,  who  holds  that  Life  is  an  extra-organic 
agent,  is  logical  in  declaring  organization  to  be  the  conse- 
quence of  Life ;  *  but  there  are  many  organicists  who 
conclude  from  certain  facts  that  organs  are  developed  by 
functions,  and  that  organization  is  a  result  of  Life.  There 
seems,  however,  to  be  some  equivoque  here.  I  cannot 
otherwise  understand  how  Mr.  Spencer  should  have  writ- 
ten :  "  There  is  one  fact  implying  that  Function  must 
be  regarded  as  taking  the  precedence  of  Structure.  Of 
the  lowest  rhizopods  which  present  no  distinctions  of 

*  It  is  because  men  converted  the  result  into  a  principle,  and  sup- 
posed that  Life  preceded  the  Organism,  that  they  were  led  to  puzzle 
themselves  over  such  facts  as  the  continuance  of  vitality  in  divided 
organisms.  Aristotle  felt  the  force  of  the  objection  :  "Plants  when 
divided  are  seen  to  live,  and  so  are  certain  insects,  as  if  still  possessing 
the  same  Vital  Principle  (fvxv)  considered  specifically  {tu  etdei)  though 
not  the  same  numericallj'  (fir)  d.pi6fj.u}).  Each  of  these  parts  has  sen- 
sation and  locomotion  for  a  time  ;  and  there  is  no  room  for  surprise  at 
their  not  continuing  to  manifest  these  properties,  seeing  that  the  organs 
necessary  for  their  preservation  are  absent."  —  Dc  Anima,  Lib.  I.  Ch. 
IV.  Compare  Basso,  Pliilos.  Naturalis  advcrsus  Aristotclcm,  Amster- 
dam, 1649,  p.  260  ;  and  Taurellus,  Contra  Cccsalinnum,  1650,  p.  850  ; 
neither  of  them  grappling  with  the  difficulty  so  firmly  as  Aristotle. 


THE   NATURE   OF   LIFE.  79 

parts,  and  nevertheless  feed  and  grow  and  move  about, 
Professor  Huxley  has  remarked  that  they  exhibit  Life 
without  Organization."  *  The  equivoque  here  arises  from 
the  practice  of  calling  all  living  bodies  "  organisms," 
even  those  destitute  of  the  differentiations  called  organs ; 
but  if  we  substitute  the  term  "  living  body "  in  lieu  of 
"  organism,"  the  equivoque  will  disappear,  and  Function 
no  longer  seem  to  precede  Structure.  Neither  Mr.  Spen- 
cer nor  Mr.  Huxley  would  affirm  that  Life  can  be  man- 
ifested without  a  living  body;  and  every  living  body 
must  have  a  structure  of  some  sort  —  unless  by  structure 
be  meant  a  special  configuration  of  parts.  The  proper- 
ties of  a  body,  whether  it  be  simple  or  complex  in  struc- 
ture, result  from  the  properties  of  its  components ;  and 
the  vital  phenomena  vary  with  these  varying  compo- 
nents. The  substance  of  a  Rhizopod  is  indeed  simple 
as  compared  with  that  of  higher  organisms,  but  is  com- 
plex as  compared  with  anorganisms ;  and  corresponding 
with  this  simplicity  of  structure  there  is  simplicity  of 
vital  function,  -j* 

89.  The  properties  of  steam  are  exhibited  by  the  kettle 
on  the  fire,  no  less  than  by  the  gigantic  engine  which 
animates  a  manufactory ;  but  the  uses  of  steam  (the 
functions  of  the  engine)  vary  with  the  varying  structure, 
and  the  applications  of  that  structure  to  other  structures. 
Precisely  analogous  is  the  case  of  the  organ  and  its  func- 
tion, in  relation  to  the  living  substance  of  which  it  is  a 
peculiar  modification.  Vital  actions  are  manifested  by 
a  lump  of  protoplasm ;  but  tliese  actions  are  as  sharply 
demarcated  from  the  actions  of  more  highly  organized 
animals,  as  the  phenomena  of  a  steam-engine  are  from 
those  of  a  teakettle. 

90.  Mr.  Spencer  has  nowhere  defined  what  he  means 

*  Si'ENCER,  Principles  nf  Biology,  ]864,  I.  153. 
t  Coinp.  Lamarck,  Philos.  Zool.,  IL  114. 


80  THE  PHYSICAL  BASIS   OF   MIND. 

by  Structure,  nor  given  a  definition  of  Organ,  and  this 
neglect  makes  it  dillicult  rightly  to  appreciate  his  view. 
But  whether  we  take  structure  to  signify  the  substance 
of  the  living  body,  or  the  differentiations  of  that  sub- 
stance into  separate  tissues  and  organs,  in  either  case  the 
actions  (functions)  of  which  this  structure  is  the  agent 
must  be  rigorously  determined  by  it.  Mr.  Spencer  has 
avowed  this  in  declaring  that  the  "general  physiologist 
may  consider  functions  in  their  widest  sense  as  the  cor- 
relatives of  tissue."  Is  this  true  in  the  widest  sense  and 
not  true  in  the  narrowest  ?  I  am  puzzled  to  find  him 
insisting  that  "function  from  beginning  to  end  is  the 
determining  cause  of  structure.  Not  only  is  this  mani- 
festly true  where  the  modification  of  structure  arises  by 
reaction  from  modification  of  function ;  but  it  is  also 
true  where  a  modification  of  structure  otherwise  produced 
apparently  initiates  a  modification  of  function."  Such 
language  would  be  consistent  were  he  a  vitalist  who 
believed  in  a  Principle  independent  of  Matter  which 
shapes  matter  into  organic  forms ;  but  as  a  positive 
thinker  he  can  scarcely  escaj)e  the  admission  that  since 
Function  is  the  activity  of  the  Agent  (Function  in  the 
widest  sense  being  the  action  of  the  whole  Organism,  and 
in  its  narrowest  sense  the  action  of  the  special  Organ) 
there  cannot  be  an  aetivity  preceding  the  agent.  I  sus- 
pect that  he  does  not  always  bear  in  mind  the  distinction 
between  Property  and  Function,  and  consequently  is  led 
into  statements  at  variance  with  the  principles  he  pro- 
fesses. As  far  as  I  understand  the  course  of  his  thought, 
it  runs  somewhat  thus :  AVitli  the  increased  use  of  an 
organ  its  volume  may  be  increased,  its  structure  altered  ; 
this  alteration  will,  by  reaction,  cause  alterations  in  other 
organs,  and  thus  the  result  of  a  change  in  the  habitual 
activities  of  an  animal  will  be  an  alteration  in  the  ar- 
rangement of  its  parts. 


THE  NATURE   OF  LIFE.  81 

91,  We  speak  loosely  of  an  organ  being  developed  by 
increased  activity ;  but  this  is  loose  speech,  and  investi- 
gation shows  that  the  organ  is  not  developed  ly,  but 
accompanies  the  increased  activity,  every  increment  of 
activity  being  necessarily  preceded  by  a  corresponding 
increment  of  structure.  This  is  evident  a  'priori:  the 
force  manifested  is  inherent  in  the  structure  manifesting 
it.  Thus  we  ought  not  to  say  "  the  vascular  system  fur- 
nishes good  instances  of  the  increased  growth  that  follows 
increased  function  "  ;  we  ought  to  say,  "  that  permits  in- 
creased function."  The  muscle  having  a  contractile  power 
represented  by  10,  expends,  we  will  suppose,  7  units  of 
force  in  its  normal  activity,  and  these  are  replaced  by  its 
normal  nutrition.  If  from  an  extra  demand  upon  it  9 
units  are  expended,  the  muscle  becomes  fatigued,  if  10, 
exhausted,  and  it  will  no  longer  contract,  the  whole  dis- 
posable sum  of  its  contractility  being  dissipated.  During 
all  these  stages  the  structure  of  the  muscle  —  or  to  pre- 
vent all  equivoque,  let  us  say  the  substance  of  the  muscle 
—  has  been  changing,  not  indeed  in  any  degree  apprecia- 
ble to  the  eye,  but  appreciable  by  the  more  decisive  tests 
of  chemical  and  pliysiological  reactions.  Yet  inasmuch  as 
in  the  ordinary  course  of  things  the  waste  is  quickly  re- 
paired, the  muscle  in  repose  once  more  regains  its  origi- 
nal state,  once  more  represents  10  units  of  contractility. 
Now  let  us  consider  what  takes  place  wlien  extra  labor  is 
thrown  upon  the  mu.scle,  when  exercise  causes  growth.  At 
the  outset  of  a  walking  tour  we  may  not  be  able  to  com- 
pass more  than  twenty  miles  a  day,  at  its  close  we  manage 
thirty.  Is  it  the  increased  activity  of  the  function  which 
has  caused  tliis  increase  of  structure  ?  In  one  sense,  yes ; 
but  let  us  understand  it.  Had  the  increase  of  activity 
been  temporary,  there  would  liave  been  only  a  temporary 
increase  of  structure.  But  wlien  the  ordinary  expendi- 
ture of  7  units  rises  to  9,  on  several  successive  days,  tliis 

4*  F 


82  THE  PHYSICAL  BASIS   OF  MIND. 

extra  expenditure  of  tissue  has  had  to  be  met  by  an  extra 
nutrition  —  i.  e.  more  plasmode  has  been  formed  and 
more  protoplasm.  It  is  a  physiological  law,  easily  ex- 
plained, that,  within  due  limits,  extra  waste  brings  about 
extra  repair :  as  the  channels  are  widened  and  raultijjlied, 
the  derived  currents  become  stronger,  and  the  increased 
flow  of  nutrition  which  was  temporary  becomes  perma- 
nent, because  this  increase  is  no  longer  dependent  on 
an  extra  stimulus,  but  on  an  enlarged  channel.*  When 
the  channels  have  not  become  multiplied  or  enlarged, 
which  must  be  the  case  whenever  the  extra  stimulus  is 
fluctuating  and  temporary,  the  extra  expenditure  is  not 
followed  by  increased  size  of  the  muscle :  the  currents 
resume  their  old  directions,  no  longer  being  diverted. 

92.  Let  the  social  organism  furnish  us  with  an  illus- 
tration. At  the  present  moment  there  is  a  movement 
against  the  retail  shopkeepers  of  London  in  favor  of  Co- 
operative Stores.  The  stimulus  of  getting  better  goods 
and  cheaper,  attracts  tlie  flow  of  custom  from  its  old  chan- 
nels ;  and  if  this  continue  a  certain  time  the  new  arrange- 
ments will  be  so  thoroughly  organized,  and  will  work  so 
easily,  that  Co-operative  Stores  will  to  a  great  extent  sup- 
plant the  retail  shops.  But  if  from  any  causes  the  stim- 
ulus slackens  before  this  reorganization  has  passed  from 
the  oscillating  into  the  permanent  stage  —  if  the  goods 
are  not  found  to  be  superior,  or  the  cheapness  not  worth 
the  extra  trouble  —  the  old  influences  (aiding  our  indo- 
lence) which  have  been  long  and  continuously  at  work, 
will  cause  the  social  organism  to  resume  its  old  aspect, 
and  the  co-operative  "varieties"  will  disappear,  or  exist 
beside  the  ancient  "  species." 

In  the  one  case  as  in  the  other  a  glance  at  the  process 
is  enough  to  detect  that  the  increase  in  the  activity  has 

*  Comp.  Spexcer,  op.  cit.,  II.  362,  363,  for  good  illustrations  of  this. 


THE   NATURE   OF  LIFE.  83 

been  preceded  by  a  corresponding  increase  in  the  struc- 
ture. The  muscle  has  not  been  enlarged  ly  extra  activ- 
ity, but  with  it.  The  co-operative  action  has  grown  Avith 
each  additional  co-operator.  Looking  at  the  cases  from 
afar  we  may  justly  say  that  development  has  been  due 
to  function ;  but  looking  to  the  process  we  see  that  each 
increment  of  activity  was  necessarily  dependent  on  an 
increment  of  substance.  When  changes  of  habit  or  adap- 
tation are  said  to  produce  modifications  in  structures,  this 
is  true  in  as  far  as  one  modification  of  structure  necessa- 
rily brings  with  it  correlative  modifications,  the  growth 
of  one  part  affecting  the  growth  of  all  more  or  less ;  but 
we  must  remember  that  to  render  the  structure  capable 
of  new  adaptations  corresponding  modifications  must  have 
been  going  on.  The  retail  shopkeepers  might  securely 
laugh  at  the  co-operative  movement  if  the  respectable 
families  would  not  or  could  not  become  co-operant. 
When  Mr.  Spencer  urges  that  "  not  only  may  leaf-stalks 
assume  to  a  great  degree  the  character  of  stems  when 
they  have  to  discharge  the  functions  of  stems  by  support- 
ing many  leaves,  and  very  large  leaves,  but  they  may 
assume  the  characters  of  leaves  when  they  have  to  under- 
take the  functions  of  leaves,"  I  would  ask  if  he  is  not 
reversing  the  actual  process  ?  The  stem  cannot  assume 
the  functions  of  a  leaf  until  it  has  first  assumed  the  char- 
acter of  a  leaf.  The  assumptions  of  both  must  be  grad- 
ual, and  pari  passu. 

93.  The  liand  is  an  organ,  its  function  is  prehension. 
Tlic  performance  of  this  function  in  any  of  its  numerous 
applications  is  rigorously  limited  l)y  the  structure  of  the 
liand  —  the  bones,  muscles,  nerves,  circulating  and  ab- 
sorbent vessels,  connective  tissue,  fat,  etc.  Fatigue  the 
nerve,  and  the  function  will  be  feebly  performed  ;  exhaust 
it,  and  the  function  ceases ;  diminish  tlie  action  of  the 
heart,  tie  an  artery,  or  vitiate  tlie  structure  of  the  blood, 


S4  THE   PHYSICAL   BASIS   OF   MIXD. 

and  the  function  will  be  correspondingly  affected ;  stiffen 
the  tendons,  soften  the  bones,  diminish  the  synovial  fluid, 
or  increase  the  fat  —  in  short,  make  any  alteration  what- 
ever in  the  structure  of  the  hand,  and  an  alteration  is 
necessarily  produced  in  its  function.  So  rigorously  is 
function  dependent  upon  structure,  that  the  hand  of  one 
man  will  execute  actions  which  are  impossible  to  another. 
The  hand  of  a  baby  is  said  to  be  the  same  in  structure  as 
the  hand  of  a  man ;  and  since  the  powers  (functions)  of 
the  two  are  notoriously  different,  we  might  rashly  con- 
clude that  here  function  was  dissociated  from  structure. 
The  case  is  illustrative.  In  baby  and  man  the  structure 
is  similar,  not  the  same ;  the  resemblance  is  of  kind,  not 
of  degree ;  and  the  function  likewise  varies  with  the  de- 
gree. The  penny  cannon  which  delights  the  child  is  sim- 
ilar in  structure  to  the  ten-j)ounder  which  batters  down 
walls ;  and  though,  speaking  generally,  we  may  say  that 
the  function  of  both  is  to  fire  gunpowder  for  human  ends, 
no  one  expects  the  penny  cannon  to  be  employed  in  war- 
fare. In  physiology,  as  in  mechanics,  the  effect  A^aries 
with  the  forces  involved. 

There  can  be  no  doubt  that  an  exaggerated  activity  will 
produce  a  modification  in  the  active  organ,  for  this  is  only 
the  familiar  case  of  increased  growth  with  increased  exer- 
cise, and  this  is  the  biological  meaning  in  which  Function 
can  be  said  not,  indeed,  to  create,  but  to  modify  an  exist- 
ing Organ.  Preceding  the  activity  there  must  be  the 
agent.  Every  organ  although  having  its  special  function 
has  also  the  properties  of  all  the  tissues  which  constitute 
it.  The  function  is  only  the  synthesis  of  these  properties 
to  which  a  dominant  tissue  gives  a  sj)ecial  character. 
The  eye,  for  example,  though  specially  characterized  by 
its  retinal  sensibility  to  light,  is  largely  endowed  with 
muscles,  and  its  movements  are  essential  to  Vision.  The 
intestinal  canal,  again,  though  specially  characterized  by 


THE   NATURE   OF   LIFE,  85 

its  secretions  for  the  decomposition  of  food,  has  muscles 
which  are  essential  to  Digestion.  In  many  animals, 
especially  vegetable-feeders,  there  is  an  exaggeration  of 
the  muscular  activity  in  certain  parts  of  the  intestinal 
canal  which  is  only  possible  through  a  corresponding  de- 
velopment of  the  muscular  tissue,  so  that  in  some  birds, 
crustaceans,  and  molluscs  we  find  a  gizzard,  which  is 
wliolly  without  a  nuicous  membrane  to  secrete  fluids,  and 
which  aids  Digestion  solely  by  trituration. 

94.  IVIr.  Spencer,  as  I  have  already  suggested,  seems 
to  have  been  led  into  his  view  by  not  keeping  distinctly 
present  to  his  mind  the  differences  between  Properties  of 
tissue  and  Function,  the  activity  of  an  organ.  "That 
function  takes  precedence  of  structure,"  he  says,  "  seems 
implied  in  the  definition  of  Life.  If  Life  consist  of  inner 
actions  so  adjusted  as  to  balance  outer  actions  —  if  the 
actions  are  the  substance  of  Life,  while  the  adjustment 
constitutes  its  form ;  then  may  we  not  say  that  the  ac- 
tions formed  must  come  before  that  which  forms  tliem  — 
that  the  continuous  change  which  is  the  basis  of  function 
must  come  before  the  structure  which  brings  tlie  function 
into  shape?"  The  separation  of  "actions  formed"  from 
"  that  wliich  forms  them "  is  inadmissible.  An  action 
cannot  come  lefore  the  agent :  it  is  the  agent  in  act.  The 
continuous  change,  which  is  the  basis  of  Vitality,  is  a 
change  of  molecular  arrangements ;  and  the  organ  whicli 
gives  a  special  direction  to  the  vital  activity,  e.  g.  whicli 
shapes  the  property  of  Contractility  into  the  function  of 
Prehension,  this  organ  must  itself  be  formed  before  it  can 
manifest  this  function.  It  is  true  that  in  one  sense  the 
organs  are  formed  by,  or  are  differentiated  in,  a  pre-exist- 
ent  organism  ;  true  that  the  general  activity  of  living  sub- 
stance must  precede  the  special  activity  of  any  organ,  as 
the  expansions  of  steam  must  precede  any  steam-engine 
action ;  but  the  general  activity  depends  on  the  general 


86  THE  PHYSICAL  BASIS   OF   MIND. 

structure ;  and  the  special  actions  on  the  special  struc- 
tures. If  by  Organization  we  are  to  understand  not  sim- 
ply organized  substance,  but  a  more  or  less  complex 
arrangement  of  that  substance  into  separate  organs,  the 
question  is  tantamount  to  asking  whether  the  simplest 
animals  and  plants  have  life  ?  And  to  ask  the  question, 
whether  Life  precedes  organic  substance  ?  is  tantamount 
to  asking  whether  the  convex  aspect  of  a  curve  precedes 
the  concave !  or  whether  the  motions  of  a  body  precede 
the  body  !  To  disengage  ourselves  from  the  complicated 
suggestions  of  such  a  word  as  Life,  let  us  consider  one  of 
the  vital  phenomena.  Contraction.  This  is  a  phenomenon 
manifested  by  simple  protoplasm,  and  by  the  highly  dif- 
ferentiated form  of  protoplasm  known  as  muscle.  In  one 
sense  it  would  be  correct  to  say  tliat  Contractility  as  a 
general  property  of  tissue  precedes  Contraction,  which  is 
specialized  in  muscle.  But  it  would  be  absurd  to  say 
that  viaiscular  contraction  preceded  the  existence  of  mus- 
cle, and  formed  it.  Tlie  contractions  of  the  protoplasm 
are  not  the  same  as  muscular  contractions  any  more  than 
the  hand  of  a  baby  is  the  same  as  a  man's ;  the  general 
property  which  both  have  in  common  depends  on  the 
substance  both  have  in  common  ;  the  special  property 
which  belongs  to  the  muscle  depends  on  its  special  struc- 
ture. An  infinite  activity  of  the  contractile  protoplasm 
would  be  incompetent  to  form  a  muscle,  unless  it  were 
accompanied  by  that  peculiar  change  in  structure  which 
constitutes  muscle.  The  teakettle  might  boil  forever 
without  producing  a  steam-engine  or  the  actions  of  a 
steam-engine.  That  which  is  true  of  one  function  is  true 
of  all  functions,  and  true  of  Life,  which  is  the  sum  of 
vital  activities. 

95.  It  is  this  haziness  which  made  Agassiz  "  regret  to 
observe  that  it  has  almost  become  an  axiom  that  iden- 
tical functions  presuppose  identical  organs.     There  never 


THE  NATURE   OF   LIFE.  87 

was  a  more  incorrect  principle  leading  to  more  injurious 
consequences."*  And  elsewhere  he  argues  that  organs 
can  exist  without  functions.  But  this  is  obviously  to 
pervert  the  fundamental  idea  of  an  organ.  "  The  teeth 
of  the  whale  which  never  eat  through  the  gums,  and  the 
breasts  of  the  males  of  all  classes  of  mammalia,"  are  cited 
by  him  as  examples  of  such  organs  without  functions ; 
but  in  the  physiological  significance  of  the  term  these  are 
not  organs  at  all.  It  is  no  more  to  be  expected  that  the 
breasts  of  the  male  should  act  in  lactation,  than  that  the 
slackened  string  of  a  violin  should  yield  nmsical  tones ; 
but  the  breasts  of  the  male  may  be  easily  stimulated  into 
yielding  milk,  and  the  slackened  string  of  the  violin  may 
be  tightened  so  as  to  yield  tone.  Even  the  breasts  of  the 
female  do  not  yield  milk  except  under  certain  conditions, 
and  in  the  absence  of  these  are  on  a  par  with  those  of  the 
male. 

96.  Organized  substance  lias  the  general  properties  of 
Assimilation,  Evolution,  Sensibility,  and  Contractility ; 
each  of  the  special  tissues  into  which  organized  substance 
is  differentiated  manifests  a  predominance  of  one  of  these 
properties.  Thus  although  the  embryo-cells  all  manifest 
contractility,  it  is  only  the  specialized  muscle-cell  which 
continues  throughout  its  existence  to  manifest  this  prop- 
erty, and  in  a  dominant  form  ;  the  muscle-cell  also  assim- 
ilates and  develops,  but  besides  having  these  properties  in 
common  witli  all  other  cells,  it  has  the  special  property 
of  contracting  with  an  energy  not  found  in  the  others. 
All  cells  respire ;  but  the  blood-cells  have  this  property 
of  absorbing  oxygen  to  a  degree  so  far  surpassing  that  of 
any  other  cell  that  physiologists  have  been  led  to  speak 
of  their  containing  a  peculiar  respiratory  substance.  In 
like  manner  all,  or  nearly  all,  the  tissues  contain  mydinr, 
—  w^hich  indeed  is  one  of  the  chief  constituents  of  the 

*  Agassiz,  Essay  on  Cla,ssification,  p.  91. 


88  THE   niYSICAL   BASIS   OF   MIND. 

yolk  of  eggs  —  but  only  in  the  wliite  sheath  of  the  nerves 
is  it  detached  and  specialized  as  a  tissue. 

97.  But  while  Sensibility  and  Contractility  are  general 
properties  of  organized  substance,  specialized  in  special 
tissues,  Sensation  and  Contraction  are  functions  of  the 
organs  formed  by  such  tissues  ;  and  these  organs  are  only 
found  in  animal  organisms.  It  is  a  serious  error,  which 
we  shall  hereafter  have  to  insist  on,  to  suppose  that  Sen- 
sation can  be  the  property  of  ganglionic  cells,  or,  as  it  is 
more  often  stated,  the  property  of  the  central  gray  matter. 
Sensation  is  the  function  of  the  organism ;  it  varies  with 
the  varying  organ ;  the  sensation  of  Touch  not  being  the 
same  as  the  sensation  of  Sight,  or  of  Sound. 

98.  AVe  may  consider  the  organism  under  two  aspects 
—  that  of  Structure  and  that  of  Function.  The  latter 
has  two  broad  divisions  corresponding  with  the  vegetal 
and  animal  lives  ;  the  one  is  Nutrient,  the  other  Efficient. 
The  one  prepares  and  distributes  Food,  the  other  distrib- 
utes ]\Iotion.  Of  course  this  separation  is  analytical.  In 
reality  the  two  are  interblended ;  and  although  the  neuro- 
muscular system  is  developed  out  of  the  nutritive  system, 
it  is  no  sooner  developed  than  it  plays  its  part  as  Instru- 
ment in  the  preparation  and  distribution  of  Aliment. 

This  not  being  a  treatise  on  Physiology,  there  can  be  no 
necessity  for  our  here  considering  the  properties  and  func- 
tions in  detail.  What  is  necessary  to  be  said  on  Sensi- 
bility and  Contractility  will  find  its  place  in  the  course 
of  future  chapters ;  for  the  present  we  will  confine  our- 
selves to  Evolution  on  account  of  its  psychological,  no 
less  than  its  physiological,  interest. 


THE  NATURE  OF  LIFE.  89 


CHAPTEE  V. 


EVOLUTION. 


99.  That  organized  substance  has  the  property  of 
nourishing  itself  by  assimilating  from  its  internal  me- 
dium substances  there  present  in  an  unorganized  state, 
and  that  this  is  followed  by  a  development  or  differentia- 
tion of  structure,  is  familiar  to  every  inquirer. 

Every  one  who  has  pursued  embryological  researches, 
and  in  a  lesser  degree  every  one  who  has  merely  read 
about  them,  must  have  been  impressed  by  this  marvel  of 
marvels  :  an  exceedingly  minute  portion  of  living  matter, 
so  simple  in  aspect  that  a  line  will  define  it,  passes  by 
successive  modifications  into  an  organism  so  complex  that 
a  treatise  is  needed  to  describe  it ;  not  only  do  the  cells 
in  which  the  ovum  and  the  spermatozoon  originate,  pass 
into  a  complex  organism,  reproducing  the  forms  and  fea- 
tures of  the  parents,  and  with  these  the  constitutional 
peculiarities  of  the  parents  (their  longevity,  their  diseases, 
their  mental  dispositions,  nay,  their  very  tricks  and  hab- 
its), but  they  may  reproduce  the  form  and  features,  the 
dispositions  and  diseases,  of  a  grandfather  or  great-grand- 
father, wliich  had  lain  dormant  in  the  father  or  mother. 
( 'onsider  for  an  instant  what  this  implies.  A  microscopic 
fell  of  albuminous  compounds,  wholly  witliout  trace  of 
organs,  not  appreciably  distinguishable  from  millions  of 
(ither  cells,  does  nevertheless  contain  within  it  tlie  "pos- 
sihilities"  of  an  organism  so  complex  and  so  special  as 
that  of  a  Newton  or  a  Napoleon.     If  ever  there  was  a  case 


90  THE   PHYSICAL   BASIS   OF   MIND. 

when  the  famous  Aristotelian  notion  of  a  "potential 
existence "  seemed  justified,  assuredly  it  is  tliis.  And 
although  we  can  only  by  a  fallacy  maintain  the  oak  to  be 
contained  in  the  acorn,  or  the  animal  contained  in  the 
ovum,  the  fallacy  is  so  natural,  and  indeed  so  difficult  of 
escape,  that  there  is  no  ground  for  surprise  when  physi- 
ologists, on  first  learning  sometliing  of  development,  were 
found  maintaining  that  the  perfect  organism  existed 
already  in  the  ovum,  having  all  its  lineaments  in  minia- 
ture, and  only  growing  into  visible  dimensions  through 
the  successive  stages  of  evolution.*  The  preformation 
of  the  organism  seemed  an  inevitable  deduction  from  the 
opinions  once  universal.  It  led  to  many  strange,  and 
some  absurd  conclusions ;  among  them,  to  the  assertion 
that  the  original  germ  of  every  species  contained  within 
it  all  the  countless  individuals  which  in  process  of  time 
miglit  issue  from  it ;  and  this  in  no  metaphysical  "  poten- 
tial "  guise,  but  as  actual  boxed-up  existences  (emboUes) ; 
so  that  Adam  and  Eve  were  in  tlie  most  literal  sense  pro- 
genitors of  the  whole  human  race,  and  contained  their 
progeny  already  shaped  within  them,  awaiting  the  great 
accoucheur,  time. 

100.  This  was  the  celebrated  "  emboitement "  theory. 
In  spite  of  obvious  objections  it  gained  scientific  accept- 
ance, because  physiologists  could  not  bring  themselves  to 
believe  tliat  so  marvellous  a  structure  as  that  of  a  human 
organism  arose  by  a  series  of  successive  modifications,  or 
because  they  could  not  comprehend  how  it  was  built  up, 
part  by  part,  into  forms  so  closely  resembling  the  parent- 
forms.  That  many  and  plausible  reasons  pleaded  in  favor 
of  this  opinion  is  evident  in  the  fact  that  illustrious  men 
like  Haller,  Bonnet,  Vallisneri,  Swammerdamm,  Eeaumur, 
and  Cuvier,  were  its  advocates ;  and  if  there  is  not  a  sin- 

*  "  Nulla  in  corpore  animali  pars  ante  aliam  facta  est,  et  omnes  simul 
creatae  existunt." —  Haller,  Elemcnta  Physioloyice,  VIII.  148. 


THE   NATURE   OF   LIFE.  91 

gle  physiologist  of  our  day  who  accepts  it,  or  who  finds 
any  peculiar  difficulty  in  following  the  demonstrations  of 
embryologists,  how  from  the  common  starting-point  of  a 
self-multiplying  epithelial  cell  parts  so  diverse  as  hairs, 
nails,  hoofs,  scales,  featliers,  crystalline  lens,  and  secreting 
glands  may  be  evolved,  or  how  from  the  homogeneous 
germinal  membrane  the  complex  organism  will  arise,  there 
are  very  few  among  the  scorners  of  the  dead  hypothesis 
who  seem  capable  of  generalizing  the  principles  which 
have  destroyed  it,  or  can  conceive  that  the  laws  of  Evo- 
lution apply  as  rigorously  to  the  animal  and  vegetable 
kingdo7ns  as  to  the  individual  organisms.  The  illustrious 
names  of  those  who  advocated  the  preformation  hypothe- 
sis may  serve  to  check  our  servile  submission  to  the 
authorities  so  loudly  proclaimed  as  advocates  of  the  fixity 
of  species.  The  more  because  the  two  doctrines  have  a 
common  parentage.  The  one  falls  with  the  other,  and  no 
array  of  authorities  can  arrest  the  fall.  That  the  mani- 
fold differentiations  noticeable  in  a  complex  organism 
should  have  been  evolved  from  a  membrane  wholly  des- 
titute of  differences  is  a  marvel,  but  a  marvel  which  Sci- 
ence has  made  intelligible.  Yet  the  majority  of  those  to 
whom  this  has  been  made  intelligible  still  find  an  impos- 
sibility in  admitting  that  the  manifold  forms  of  plant  and 
animal  were  successively  evolved  from  equally  simple 
origins.  They  relinquish  the  hypothesis  of  preformation 
in  the  one  case,  and  cling  to  it  in  the  other.  Evolution, 
demonstralile  in  the  individual  history,  seems  prepos- 
terous in  the  history  of  the  class.  And  thus  is  pre- 
sented the  instructive  spectacle  of  pliilosophers  laughing 
at  the  absurdities  of  "  preformation,"  and  yet  exerting  all 
their  logic  and  rhetoric  in  defence  of  "  creative  fiats " 
—  which  is  simply  the  preformation  liypothesis  "  writ 
large." 

101.    It  would  not  be  difficult  to  show  that  tlie  doc- 


92  THE    I'HYSICAL    BASIS    OF    MIXD. 

trine  of  Epigenesis,  with  which  "Wolff  forever  displaced 
the  doctrine  of  Preformation,  leads  by  an  inevitable  logic 
to  the  doctrine  of  universal  Evolution ;  and  that  we  can 
no  more  undei'stand  the  appearance  of  a  uew  organism 
which  is  not  the  modification  of  some  already  existing 
organism,  than  we  can  understand  the  sudden  appearance 
of  a  new  organ  which  is  not  the  modification  of  some 
existing  structure.  In  the  one  case  as  in  the  other  we 
may  disguise  the  process  under  such  terms  as  creative 
fiat  and  preformation ;  but  these  terms  are  no  explana- 
tions ;  they  re-state  the  results,  they  do  not  describe  the 
process ;  whereas  Epigenesis  describes  the  process  as  it 
passes  under  the  eye  of  science. 

102.  If  any  reader  of  these  pages  who,  from  theo- 
logical or  zoological  suspicion  of  the  Develoj)ment  Hy- 
pothesis, clings  to  tlie  hyjDothesis  of  a  creative  Plan  which 
once  for  all  arranged  the  organic  world  in  Types  that 
could  not  change,  will  ask  what  rational  interpretation 
can  be  given  to  the  succession  of  phases  each  embryo  is 
forced  to  pass  through,  it  may  help  to  give  him  pause. 
He  will  observe  that  none  of  these  phases  have  any  adap- 
tation to  the  future  state  of  the  animal,  but  are  in  positive 
contradiction  to  it,  or  are  simply  purposeless  ;  whereas 
all  show  stamped  on  them  the  unmistakable  characters 
of  ancestral  adaptations  and  the  progressions  of  Organic 
Evolution.  What  does  the  fact  imply  ?  There  is  not  a 
single  known  example  of  a  complex  organism  wliicli  is 
not  developed  out  of  simpler  forms.  Before  it  can  attain 
the  complex  structure  which  distinguishes  it,  there  must 
be  an  evolution  of  forms  similar  to  those  which  distin- 
guish the  structures  of  organisms  lower  in  the  series. 
On  the  hypothesis  of  a  Plan  which  prearranged  tlie  or- 
ganic world,  nothing  could  be  more  unworthy  of  a  su- 
preme intelligence  than  this  inability  to  construct  an 
organism   at   once,   witliout   previously   making   several 


THE   NATURE   OF   LIFE.  93 

tentative  efforts,  undoing  to-day  what  was  so  carefully 
done  yesterday,  and  repeating  for  centuries  the  same  ten- 
tatixcs,  and  the  same  corrections,  in  the  same  succession. 
Do  not  let  us  blink  this  consideration.  There  is  a  tra- 
ditional phrase  much  in  vogue  among  the  anthropomor- 
phists,  which  arose  naturally  enough  from  the  tendency 
to  take  human  methods  as  an  explanation  of  the  divine 
—  a  phrase  which  becomes  a  sort  of  argument  —  "  The 
Great  Architect."  But  if  we  are  to  admit  the  human 
point  of  view,  a  glance  at  the  facts  of  embryology  must 
produce  very  uncomfortable  reflections.  For  what  should 
we  say  to  an  architect  who  was  unable,  or  being  able  was 
obstinately  unwilling,  to  erect  a  palace  except  by  first 
using  his  materials  in  the  shape  of  a  hut,  then  pulling  it 
down  and  rebuilding  them  as  a  cottage,  then  adding  story 
to  story  and  room  to  room,  not  with  any  reference  to  the 
ultimate  purposes  of  the  palace,  but  wholly  with  reference 
to  the  way  in  which  houses  were  constructed  in  ancient 
times  ?  What  should  we  say  to  the  architect  who  could 
not  form  a  museum  out  of  bricks  and  mortar,  but  was 
forced  .to  begin  as  if  going  to  build  a  mansion :  and  after 
proceeding  some  way  in  this  direction,  altered  his  plan 
into  a  palace,  and  that  again  into  a  museum  ?  Yet  this 
is  the  sort  of  succession  on  which  organisms  are  con- 
structed. The  fact  has  long  been  familiar;  how  has  it 
been  reconciled  with  Infinite  Wisdom  ?  Let  the  follow- 
ing passage  answer  for  a  thousand  :  —  "  The  embryo  is 
nothing  like  the  miniature  of  the  adult.  For  a  long 
while  the  body  in  its  entirety  and  its  details  presents 
the  strangest  of  spectacles.  Day  by  day  and  hour  by 
hour  the  aspect  of  the  scene  changes,  and  this  instability 
is  exhibited  by  the  most  essential  parts  no  less  than  by 
the  accessory  parts.  One  would  say  that  Nature  feels  her 
way,  and  only  reaches  the  goal  after  many  times  missing 
the  path,  —  on  dirait  que  la  nature  tatonnc  et  ne  conduit 


94  THE   PHYSICAL   BASIS   OF   MIND. 

son  ceuvre  i\  bon  fin  qii'apres  s'etre  souvent  trompee."  * 
Writers  have  no  compunction  in  speaking  of  Nature  feel- 
ing her  Avay  and  blundering ;  but  if  in  lieu  of  Nature, 
which  may  mean  anything,  the  Great  Architect  be  sub- 
stituted, it  is  probable  that  the  repugnance  to  using  such 
language  of  evasion  may  cause  men  to  revise  their  con- 
ceptions altogether ;  they  dare  not  attribute  ignorance 
and  incompetence  to  the  Creator. 

103.  Obviously  the  architectural  hypothesis  is  incom- 
petent to  explain  the  phenomena  of  organic  development. 
Evolution  is  the  universal  process  ;  not  creation  of  a 
direct  kind.  Von  Baer,  who  very  properly  corrected  the 
exaggerations  which  had  been  put  forth  respecting  the 
identity  of  the  embryonic  forms  with  adult  forms  lower 
in  the  scale,  who  showed  that  the  mammalian  embryo 
never  was  a  bird,  a  reptile,  or  a  fish,  nevertheless  empha- 
sized the  fact  that  the  mammalian  embryo  passes  through 
all  the  lower  typical  forms  ;  so  much  so  that,  except  by 
their  size,  it  is  impossible  to  distinguish  the  embryos  of 
mammal,  bird,  lizard,  or  snake.  "  In  my  collection,"  he 
says,  "  there  are  two  little  embryos  which  I  have  omitted 
to  label,  so  that  I  am  now  quite  incompetent  to  say  to 
what  class  they  belong.  They  may  be  lizards,  they  may 
be  small  birds,  or  very  young  mammals ;  so  complete  is 
the  similarity  in  the  mode  of  formation  of  the  head  and 
trunk.  The  extremities  have  not  yet  made  their  appear- 
ance. But  even  if  they  existed  in  the  earliest  stage  we 
should  learn  nothing  from  them,  for  the  feet  of  lizards, 
mammals,  and  the  wings  of  birds,  all  arise  from  the  same 
common  form."  He  sums  up  with  his  formula :  "  The 
special  type  is  always  evolved  from  a  more  general 
type."t 

*  QuATREFAGES,  Metamorphoses  de  V Homme  et  des  Jnimaux,  1862, 
p.  42. 

t  Von  Baer,  Ueber  Entwickelungsgeschichte,  1828,  I.  221. 


THE   NATURE   OF   LIFE.  95 

Such  reminiscences  of  earlier  forms  are  intelligible  on 
the  supposition  that  originally  the  later  form  was  a  modi- 
fication of  the  earlier  form,  and  that  this  modification  is 
repeated ;  or  on  the  supposition  that  there  was  a  similar- 
ity in  the  organic  conditions,  which  similarity  ceased  at 
the  point  where  the  new  form  emerged.  But  on  no  hy- 
pothesis of  creative  Plan  are  they  intelligible.  They  are 
useless  structures,  failing  even  to  subserve  a  temporary 
purpose.  Sometimes,  as  Mr.  Darwin  remarks,  a  trace  of 
the  embryonic  resemblance  lasts  till  a  late  age :  "  Thus 
birds  of  the  same  genus,  and  of  closely  allied  genera, 
often  resemble  each  other  in  their  first  and  second  plum- 
age :  as  we  see  in  the  spotted  feathers  in  the  thrush 
group.  In  the  cat  tribe  most  of  the  species  are  striped 
and  spotted  in  lines ;  and  stripes  or  spots  can  plainly  be 
distinguished  in  the  whelp  of  the  lion  and  the  puma. 
We  occasionally,  though  rarely,  see  something  of  this 

kind  in  plants The  points  of  structure  in  which 

the  embryos  of  widely  different  animals  of  the  same  class 
resemble  each  other  often  have  no  direct  relation  to  their 
conditions  of  existence.  We  cannot,  for  instance,  suppose 
that  in  the  embryos  of  the  vertebrata  the  peculiar  loop- 
like courses  of  the  arteries  near  the  bronchial  slits  are  re- 
lated to  similar  conditions  in  the  young  mammal  which 
is  nourished  in  the  womb  of  its  mother,  in  the  egg  of  a 
bird  which  is  hatched  in  a  nest,  and  in  the  spawn  of  a 
frog  under  water." 

104.  It  would  be  easy  to  multiply  examples,  but  I 
wiU  content  myself  with  tliree.  The  tadpole  of  the  Sala- 
mander has  gills,  and  passes  his  existence  in  tlie  water ; 
but  the  tSnlamandra  atra,  which  lives  high  up  among  the 
mountains,  brings  forth  its  young  full-formed.  This  ani- 
mal never  lives  in  tlie  water.  Yet  if  we  open  a  gravid 
female,  we  find  tadpoles  inside  her  with  exquisitely  feath- 
ered gills,  and  (as  I  have  witnessed)  these  tadpoles  "  when 


96  THE   niYSICAL   BASIS   OF   MIND. 

from  tlio  mother's  womb  untimely  ripped,"  if  placed  in 
water,  swim  about  like  the  tadpoles  of  water  newts.  Ob- 
viously this  aquatic  organization  has  no  reference  to  the 
future  life  of  the  animal,  nor  has  it  any  adaptation  to  its 
embryonic  condition ;  it  has  solely  reference  to  ancestral 
forms,  it  repeats  a  phase  in  the  development  of  its  pro- 
genitors. Again,  in  the  embryo  of  the  naked  Nudibranch, 
we  always  observe  a  shell,  although  the  animal  is  without 
a  shell,  and  there  can  be  no  purpose  served  by  the  shell 
in  embryonic  life.*  Finally,  the  human  embryo  has  a 
tail,  which  is  of  course  utterly  purposeless,  and  which, 
although  to  be  explained  as  a  result  of  organic  laws,  is 
on  the  creative  hypothesis  only  explained  as  an  ad- 
herence to  the  general  plan  of  structure  —  a  specimen 
of  pedantic  trifling  "  worthy  of  no  intellect  above  the 
pongo's."  t 

105.  Humanly  appreciated,  not  only  is  it  difficult  to 
justify  the  successive  stages  of  development,  the  inces- 
sant building  up  of  structures  immediately  to  be  taken 
down,  but  also  to  explain  why  development  was  necessary 

*  Curiously  enough,  while  the  Nudibranch,  which  is  without  a  shell, 
possesses  one  during  its  embryonic  life,  there  is  another  mollusc,  Ncritina 
fluviatilis,  which  possessing  a  shell  in  its  subsequent  life  is  without  one 
during  the  early  periods,  and  according  to  CLArAKEDE  begins  an  inde- 
pendent existence,  capable  of  feeding  itself  before  it  acquires  one.  See 
his  admirable  memoir  on  the  Neritina,  in  Miiller's  Archiv,  1857. 

+  Has  any  advocate  of  the  hypothesis  that  animals  were  created  as  we 
.see  them  now,  fully  formed  and  wondrously  adapted  in  all  their  parts  to 
the  conditions  in  which  they  live,  ever  considered  the  hind  legs  of  the 
seal,  which  he  may  have  watched  in  the  Zoological  Gardens  ?  Here  is  an 
animal  which  habitually  swims  like  a  fish,  and  cannot  use  his  hind  limbs 
except  as  a  rudder  to  propel  him  through  the  water  ;  but  instead  of  hav- 
ing a  fi,sh-like  tail  he  has  two  legs  flattened  together,  and  nails  on  the 
toes  —  toes  and  nails  being  obvious  superfluities.  Now  which  is  the 
more  rational  interpretation,  that  these  limbs,  in  spite  of  their  non- 
adaptation,  were  retained  in  rigid  adherence  to  a  Plan,  or  that  the  limbs 
were  inherited  from  an  ancestor  who  used  them  as  legs,  and  that  these 
legs  have  gradually  become  modified  by  the  fish-like  habits  of  the  seal  ? 


THE  NATUEE   OF  LIFE,  97 

at  all.  Why  are  not  plants  and  animals  formed  at  once, 
as  Eve  was  mythically  affirmed  to  be  taken  from  Adam's 
rib,  and  Minerva  from  Jupiter's  head  ?  The  theory  of 
Evolution  answers  this  question  very  simply  ;  the  theory 
of  Creation  can  only  answer  it  by  affirming  that  such  was 
the  ordained  plan.  But  the  theory  of  Evolution  not  only 
gives  the  simpler  and  more  intelligible  answer  to  this 
question,  it  gives  an  answer  to  the  further  question  which 
leaves  the  theory  of  Creation  no  loophole  except  a  soph- 
ism —  namely,  why  the  formation  of  organisms  is  con- 
stantly beiug  frustrated  or  perverted  ?  And,  further,  it 
gives  an  explanation  of  the  law  noticed  by  Milne  Ed- 
wards, that  Nature  is  as  economical  in  her  means  as  she 
is  prodigal  in  her  variation  of  them  :  "  On  dirait  qu'avant 
de  recourir  a  des  ressources  nouvelles  elle  a  voulu  q)uiser, 
en  quelque  sorte,  chacun  des  precedes  qu'elle  avait  mis 
en  jeu."  *  The  aj^plause  bestowed  on  Nature  for  being 
economical  is  a  curious  transference  to  Nature  of  human 
necessities.  Why,  with  a  whole  universe  at  her  disposal, 
should  Nature  be  economical  ?  Why  must  she  always  be 
working  in  the  same  groove,  and  using  but  a  few  out  of 
the  many  substances  at  her  command  ?  Economy  is  a 
virtue  only  in  the  poor.  If  Nature,  in  organic  evolutions, 
is  restricted  to  a  very  few  substances,  and  a  very  few 
modes  of  combination,  always  creating  new  forms  by 
modification  of  the  old,  and  apparently  incapable  of  creat- 
ing an  organism  at  once,  this  must  imply  an  inherent 
necessity  which  is  very  unlike  the  free  choice  that  can 
render  economy  a  merit. 

lOG.  There  may  indeed  be  raised  an  objection  to  the 
Development  Hypothesis  on  the  ground  tliat  if  the  com- 
plex forms  were  all  developed  from  the  simpler  forms,  we 
ought  to  trace  the  identities  through  all  their  stages.  If 
the  fi.sh  developed  into  the  reptile,  the  reptile  into  the 

*  Milne  Edwards,  Intro,  d  la  Zoolugie  Giniralc,  1851,  p.  9. 

VOL.  III.  5  o 


98  THE   PHYSICAL   BASIS   OF   MIND. 

bird,  and  the  bird  into  the  mammal  (wliich  I,  for  one, 
think  (questionable),  we  ought  to  find,  it  is  urged,  evidence 
of  this  passage.  And  at  one  time  it  was  asserted  that  the 
evidence  existed ;  but  this  has  been  disproved,  and  on 
the  disproof  the  opponents  of  Evolution  take  their  stand. 
Although  I  cannot  feel  much  confidence  in  the  idea  of 
such  a  passage  from  Type  to  Type,  and  although  the  pas- 
sage, if  ever  it  occurred,  must  have  occurred  at  so  remote 
a  period  as  to  leave  no  evidence  more  positive  than  infer- 
ence, I  cannot  but  think  the  teaching  of  Embryology  far 
more  favorable  to  it  than  to  our  opponents.  Supposing,  for 
the  sake  of  argument,  that  the  passage  did  take  place, 
ought  we  to  find  the  embryonic  stages  accurately  repro- 
ducing the  permanent  forms  of  lower  types  ?  Yon  Baer 
thinks  we  ought ;  and  lesser  men  may  follow  him  without 
reproach.  But  it  seems  to  me  that  he  starts  from  an 
inadmissible  assumption,  namely,  that  the  development 
must  necessarily  be  in  a  straight  line  rather  than  in  a 
multiplicity  of  divergent  lines.  "  When  we  find  the  em- 
bryonic condition,"  he  says,  "  differing  from  the  adult,  we 
ought  to  find  a  corresponding  condition  somewhere  in  the 
lower  animals."  *  Not  necessarily.  We  know  that  the 
mental  development  of  a  civilized  man  passes  through 
the  stages  which  the  race  passed  through  in  the  course  of 
its  long  history,  and  the  psychology  of  the  child  repro- 
duces the  psychology  of  the  savage.  But  as  this  develop- 
ment takes  place  under  conditions  in  many  respects  dif- 
ferent, and  as  certain  phases  are  hurried  over,  we  do  not 
expect  to  find  a  complete  parallel.  It  is  enough  if  we 
can  trace  general  resemblances.  Yon  Baer  adds,  "  That 
certain  correspondences  should  occur  between  the  embry- 
onic states  of  some  animals  and  the  adult  states  of  others 
seems  inevitable  and  of  no  significance  (?).  They  could 
not  fail,  since  the  embryos  lie  within  the  animal  sphere, 

*  Von  Baer,  o^.  ciL,  I.  203. 


THE   NATURE   OF  LIFE.  99 

and  the  variations  of  wliicli  the  animal  body  is  capable 
are  determined  for  each  type  by  the  internal  connection 
and  mutual  reaction  of  its  organs,  so  that  particular  repe- 
titions are  inevitable."  A  profound  remark,  to  which  I 
shall  hereafter  have  occasion  to  return,  but  its  bearing  on 
the  present  question  is  inconclusive.  The  fact  that  the 
embryonic  stages  of  the  higher  animals  resemble  in  gen- 
eral cliaracters  the  jDcrmanent  stages  of  the  lower  animals, 
and  very  closely  resemble  the  embryonic  stages  of  those 
animals,  is  all  that  the  Development  Hypothesis  requires. 
Nor  is  its  value  lessened  by  the  fact  that  many  of  tlie 
details  and  intermediate  stages  seem  passed  over  in  the 
development  of  the  higher  forms,  for  the  recapitulation 
can  only  be  of  outlines,  not  of  details ;  since  there  are 
differences  in  the  forms,  there  must  be  differences  in 
their  histories. 

107.  In  the  preceding  observations  the  object  has  sim- 
ply been  to  show  that  tlie  phenomena  to  be  explained  can 
be  rationally  conceived  as  resulting  from  gradual  Evolu- 
tion, whereas  they  cannot  be  so  rationally  interpreted  on 
any  other  hypothesis.  And  here  it  may  be  needful  to  say 
a  word  respecting  Epigenesis. 

The  Preformation  hypothesis,  which  regarded  every 
organism  as  a  simple  educt  and  not  tlie  product  of  a  germ, 
was  called  by  its  advocates  an  evolution  hypothesis  — 
meaning  that  the  adult  form  was  an  outgrowth  of  the 
germ,  the  miniature  magnified.  Wolff,  who  replaced  that 
conception  by  a  truer  one,  called  his,  by  contrast,  Epige- 
nesis, meaning  that  there  was  not  simply  oii^-growth  but 
new  growth.  "  The  various  parts,"  he  says,  "  arise  one 
after  the  other,  so  that  always  one  is  secreted  from  {exccr- 
nirt),  or  deposited  (deponirt)  on  the  other ;  and  then  it  is 
either  a  free  and  independent  part,  or  is  only  fixed  to  that 
which  gave  it  existence,  or  else  is  contained  within  it. 
So  that  every  part  is  the  effect  of  a  2'>Te-existing  part,  and  in 


100  THE   niYSICAL   BASIS   OF  MIND. 

turn  the  cause  of  a  succeeding  part."  *  The  last  sentence 
expresses  the  concei:»tiou  of  Epigenesis  which  enibryolo- 
gists  now  adopt ;  and  having  said  this,  we  may  admit  that 
Wolff,  in  combating  the  error  of  preformation,  replacing 
it  witli  tlie  truer  notion  of  gradual  and  successive  forma- 
tion, was  occasionally  open  to  the  criticism  made  by  Von 
Baer,  that  he  missed  the  true  sense  of  Evolution,  since 
the  new  parts  are  not  added  on  to  the  old  parts  as  new 
formations,  but  evolved  from  them  as  transformations. 
"  The  word  Evolution,  therefore,  seems  to  me  more  de- 
scriptive of  the  process  than  Epigenesis.  It  is  true  that 
the  organism  is  not  preformed,  but  the  course  of  its  devel- 
opment is  precisely  the  course  which  its  parents  formerly 
passed  through.  Thus  it  is  the  Invisible  —  the  course  of 
development  —  which  is  p^redetermined." -f-  "When  the 
word  Epigenesis  is  used,  therefore,  the  reader  will  under- 
stand it  to  signify  that  necessary  succession  which  deter- 
mines the  existence  of  new  forms.  Just  as  the  formation  of 
chalk  is  not  the  indifferent  product  of  any  combination  of 
its  elements,  carbon,  oxygen,  and  calcium,  but  is  the  product 
of  only  one  series  of  combinations,  an  evolution  through 
necessary  successions,  the  carbon  uniting  with  oxygen  to 
form  carbonic  acid,  and  this  combining  with  the  oxide  of 
calcium  to  form  chalk,  so  likewise  the  formation  of  a 
muscle,  a  bone,  a  limb,  or  a  joint  has  its  successive  stages, 
each  of  which  is  necessary,  none  of  which  can  be  trans- 
posed. The  formation  of  bone  is  peculiarly  instructive, 
because  the  large  proportion  of  inorganic  matter  in  its 
substance,  and  seemingly  deposited  in  the  organic  tissue, 
would  lead  one  to  suppose  that  it  was  almost  an  acci- 
dental formation,  which  might  take  place  anywhere  ;  yet 

*  Wolff,  Theorie  der  Generation,  1764,  §  67.  The  reader  will  find 
abundant  and  valuable  corroboration  of  this  biological  principle  in  Siu 
James  Paoet's  LeHures  on  Surgical  Palholof))/. 

t  Von  Baer,  Selbstbiographie,  1866,  p.  319. 


THE  NATURE  OF  LIFE.  101 

although  what  is  called  connective  tissue  will  ossify  under 
certain  conditions,  true  bone  is  the  product  of  a  very  pe- 
culiar modification,  which  almost  always  needs  to  be  pre- 
ceded by  cartilage.  That  the  formation  of  bone  has  its 
special  history  may  be  seen  in  the  fact  that  it  is  the  last 
to  appear  in  the  animal  series,  many  highly  organized 
iishes  being  without  it,  and  all  the  other  systems  appear- 
ing before  it  in  the  development  of  the  embryo.  Thus 
although  the  mother's  blood  furnishes  all  the  requisite 
material,  the  fcetus  is  incapable  of  assimilating  this  ma- 
terial and  of  forming  bone,  until  its  own  development  has 
reached  a  certain  stage.  Moreover,  when  ossification  does 
begin,  it  generally  begins  in  the  skull  (in  man  in  the  clav- 
icle) ;  and  the  only  approach  to  an  internal  skeleton  in 
the  Invertebrates  is  the  so-called  skull  of  the  Cephalo- 
poda. Not  only  is  bone  a  late  development,  but  cartilage 
is  also  ;  and  although  it  is  an  error  to  maintain  that  the 
Invertebrates  are  wholly  destitute  of  cartilage,  its  occa- 
sional presence  having  been  fully  proved  by  Claparede 
and  Gegenbaur,  tlie  rarity  of  its  presence  is  very  signifi- 
cant. The  animals  which  can  form  shells  of  chalk  and 
chitine  are  yet  incapable  of  forming  even  an  approach 
to  bone. 

108.  Epigenesis  depends  on  tlie  laws  of  succession, 
which  may  be  likened  to  the  laws  of  crystallization,  if  we 
l)ear  in  mind  the  essential  differences  between  a  crystal 
and  an  organism,  the  latter  retaining  its  individuality 
through  an  incessant  molecular  change,  the  former  only 
by  the  exclusion  of  all  change.  When  a  crystalline  solu- 
tion takes  shape,  it  will  always  take  a  definite  shape, 
which  represents  what  may  be  called  tlie  directum  of  its 
Corccs,  jhc  polarity  of  its  constituent  molecules.  In 
like  manner,  when  an  organic  plasmode  takes  shape  — 
crystallizes,  so  to  speak  —  it  always  assumes  a  specific 
shape  dependent  on  the  polarity  of  its  molecules.     Crys- 


102  THE   PHYSICAL   BASIS   OF  MIND. 

tallographers  liave  determined  the  several  forms  possible 
to  crystals ;  histologists  have  recorded  the  several  forms 
of  Organites,  Tissues,  and  Organs.  Owing  to  the  greater 
variety  in  elementary  composition,  there  is  in  organic 
substance  a  more  various  polar  distribution  than  in  crys- 
tals ;  nevertheless,  there  are  sharply  defined  limits  never 
overstepped,  and  these  constitute  what  may  be  called  the 
specific  forms  of  Organites,  Tissues,  Organs,  Organisms. 
An  epithelial  cell,  for  example,  may  be  ciliated  or  colum- 
nar, a  muscle-fibre  striated  or  non-striated,  a  nerve-fibre 
naked  or  enveloped  in  a  sheath,  but  the  kind  is  always 
sharply  defined.  An  intestinal  tube  may  be  a  uniform 
canal,  or  a  canal  differentiated  into  several  unlike  com- 
partments, with  several  unlike  glandular  appendages.  A 
spinal  column  may  be  a  uniform  solid  axis,  or  a  highly 
diversified  segmented  axis.  A  limb  may  be  an  arm,  or 
a  leg,  a  wing,  or  a  paddle.  In  every  case  the  anatomist 
recognizes  a  specific  type.  He  assigns  the  uniformities  to 
the  uniformity  of  the  substance  thus  variously  shaped, 
under  a  history  which  has  been  similar ;  the  diversities 
he  assigns  to  the  various  conditions  under  which  the  pro- 
cesses of  growth  have  been  determined.  He  never 
expects  a  muscular  tissue  to  develop  into  a  skeleton,  a 
nervous  tissue  into  a  gland,  an  osseous  tissue  into  a  sen- 
sory organ.  He  never  expects  a  tail  to  become  a  hand  or 
a  foot,  though  he  sees  it  in  monkeys  and  marsupials  serv- 
ing the  offices  of  prehension  and  locomotion.  He  never 
expects  to  find  fingers  growing  anywhere  except  from 
metacarpal  bones,  or  an  arm  developed  from  a  skull.  The 
well-known  generalization  of  Geoffroy  St.  Hilaire  that  an 
organ  is  more  easily  annihilated  than  transposed,  points 
to  the  fundamental  law  of  Epigenesis.  In  the  same 
direction  point  all  the  facts  of  growth.  Out  of  a  formless 
germinal  membrane  we  see  an  immense  variety  of  forms 
evolved  ;  and  out  of  a  common  nutritive  fluid  this  variety 


THE   NATURE   OF  LIFE.  103 

of  organs  is  sustained,  repaired,  replaced ;  and  tins  not 
indifferently,  not  casually,  but  according  to  rigorous  laws 
of  succession ;  that  which  precedes  determining  that 
which  succeeds  as  inevitably  as  youth  precedes  maturity, 
and  maturity  decay.  The  nourishment  of  various  organs 
from  plasmodes  derived  from  a  common  fluid,  each  select- 
ing from  that  fluid  only  those  molecules  that  are  like  it-s 
own,  rejecting  all  the  rest,  is  very  similar  to  the  forniation 
of  various  crystals  in  a  solution  of  different  salts,  each 
salt  separating  from  the  solution  only  those  molecules 
that  are  like  itself  Reil  long  ago  called  attention  to  thi-s 
analogy.  He  observed  that  if  in  a  solution  of  nitre  and 
sulpliate  of  soda  a  crystal  of  nitre  be  dropped,  all  the  dis- 
solved nitre  crystallizes,  the  sulphate  remaining  in  solu- 
tion ;  whereas  on  reversing  the  experiment,  a  crystal  of 
sulphate  of  soda  is  found  to  crystallize  all  the  dissolved 
sulphate,  leaving  the  nitre  undisturbed.  In  like  manner 
muscle  selects  from  the  blood  its  own  materials  which  are 
there  in  solution,  rejecting  those  which  the  nerve  will 
select. 

109.  Nay,  so  definite  is  the  course  of  growth,  that  when 
a  limb  or  part  of  a  limb  is  cut  off  from  a  crab  or  salaman- 
der, a  new  limb  or  new  part  is  reproduced  in  the  old  spot, 
exactly  like  the  one  removed.  Bonnet  startled  the  world 
by  tlie  announcement  that  the  Nals,  a  worm  common  in 
])onds,  spontaneously  divided  itself  into  two  worms  ;  and 
that  when  he  cut  it  into  several  j)ieces,  each  piece  repro- 
duced head  and  tail,  and  grew  into  a  perfect  worm.  Thi« 
had  Itcen  accepted  by  all  naturalists  without  demur,  until 
Dr.  "VVilliams,  in  liis  "Iteport  on  I'ritisli  Annelida,  1851," 
declared  it  to  be  a  fable.  In  1858,  under  the  impulse  of 
Dr.  Williams's  very  emphatic  denial,  I  rc]teate<l  experi- 
ments similar  to  those  of  15onnet,  with  similar  results.  I 
cut  two  worms  in  half,  and  tlirew  away  the  head-bearing 
segments,  placing  the  others  in  two  separate  vessels,  with 


104  THE   PHYSICAL   BASIS   OF   MIND. 

iiotliiiii'  but  water  and  a  little  mud,  wliicli  was  first  care- 
fully  inspected  to  see  that  no  worm  lay  concealed  therein. 
In  a  few  days  the  heads  were  completely  reformed,  and  I 
had  the  pleasure  of  watching  them  during  their  recon- 
struction. When  the  worms  were  quite  perfect,  I  again 
cut  away  their  heads,  and  again  saw  these  reformed.  This 
was  repeated,  till  I  had  seen  four  heads  reproduced ;  after 
which  the  w^orms  succumbed. 

110.  The  question  naturally  arises.  Why  does  the  nu- 
tritive fluid  furnish  only  material  which  is  formed  into  a 
part  like  the  old  one,  instead  of  reproducing  another  part, 
or  one  having  a  somewhat  different  structure  ?  The  an- 
swer to  this  question  is  the  key  to  the  chief  problem  of 
organic  life.  That  a  limb  in  situ  should  replace  its  mo- 
lecular waste  by  molecules  derived  from  the  blood,  seems 
intelligible  enough  (because  we  are  familiar  with  it),  and 
may  be  likened  to  the  formation  of  crystals  in  a  solution  ; 
but  how  is  it  that  the  limb  ivhich  is  not  in  existence  can 
assimilate  materials  from  the  blood  ?  How  is  it  that  tlie 
blood,  wliich  elsewhere  in  the  organism  will  form  other 
parts,  here  will  only  form  this  particular  part  ?  There  is, 
probably,  no  one  who  has  turned  his  attention  to  these 
subjects  who  has  not  paused  to  consider  this  mystery. 
The  most  accredited  answer  at  present  before  the  world  is 
one  so  metaphysiological  that  I  should  pass  it  by,  were 
it  not  intimately  allied  with  that  conception  of  Species, 
wdiich  it  is  the  object  of  these  pages  to  root  out.  It 
is  this : 

111.  The  organism  is  determined  by  its  Type,  or,  as 
the  Germans  say,  its  Idea.  All  its  parts  take  shape 
according  to  this  ruling  plan ;  consequently,  when  any 
part  is  removed,  it  is  reproduced  according  to  the  Idea  of 
tlie  whole  of  which  it  forms  a  part.  Milne  Edwards,  in 
a  very  interesting  and  suggestive  work,  concludes  his  sur- 
vey of  organic  phenomena  in  these  words:  "Dans  I'or- 


THE  NATURE   OF  LIFE.  105 

ganisme  tout  semble  calcule  en  vue  d'un  resultat  deter- 
mine,  et  I'harmonie  des  parties  ne  resulte  pas  de  rinfluence 
qu'elles  peuvent  exercer  les  unes  sur  les  autres,  mais  de 
leur  co-ordination  sous  I'empire  d'une  puissance  commune, 
d'un  plan  preconcu,  d'une  force  pre-existante."*  This  is 
eminently  metapliysiological.  It  refuses  to  acknowledge 
the  operation  of  immanent  properties,  refuses  to  admit 
that  the  harmony  of  a  complex  structure  results  from  the 
mutual  relations  of  its  parts,  and  seeks  outside  the  organ- 
ism for  some  mysterious  force,  some  plan,  not  otherwise 
specified,  which  regulates  and  shapes  the  parts.  Von 
Baer,  in  his  great  work,  has  a  section  entitled,  "  The  na- 
ture of  the  animal  determines  its  development";  and  he 
thus  explains  himself:  "Although  every  stage  in  devel- 
opment is  only  made  possible  by  the  j)re-existing  condi- 
tion [which  is  another  mode  of  expressing  Epigenesis], 
nevertheless  the  entire  development  is  ruled  and  guided 
by  the  Nature  of  the  animal  which  is  about  to  be  (von 
der  gesammten  Wesenheit  des  Thieres  welches  werden 
soil),  and  it  is  not  the  momentary  condition  which  alone 
and  absolutely  determines  the  future,  but  more  general 
and  higher  relations." -f  One  must  always  be  slow  in 
rejecting  tlie  thoughts  of  a  master,  and  feel  sure  that  one 
sees  tlie  source  of  the  error  before  regarding  it  as  an  error ; 
but  in  the  present  case  I  think  the  positive  biologist  will 
1)0  at  no  loss  to  assign  Von  Baer's  error  to  its  metaphys- 
ical origin.  Without  pausing  here  to  accumulate  exam- 
ples both  of  anomalies  and  slighter  deviations  which  are 
demonstrably  due  to  the  "  momentary  conditions "  that 
preceded  them,  let  us  simply  note  the  logical  inconsist- 
ency of  a  position  which,  while  assuming  that  evenj  sepa- 
rate starje  in  development  is  the  necessary  sequence  of  its 
predecessor,  declares  the  vjholc  of  the  stages  independent 

*  Milne  Edwards,  hitro.  u  la  Zoologic  Gmeralc,  176. 
+  Von  Baku,  Uchcr  EiUwicJcclungsgcschichtc,  I.  147. 


106  THE   PHYSICAL  BASIS   OF   MIND. 

of  such  relations  !  Such  a  position  is  indeed  reconcilable 
on  the  assumption  that  animal  forms  are  moulded  "  like 
clay  in  the  hands  of  the  potter."  But  this  is  a  theologi- 
cal dogma,  which  leads  to  very  preposterous  and  impious 
conclusions ;  and  whether  it  leads  to  these  conclusions  or 
to  others,  positive  Biology  declines  theological  explana- 
tions altogether.  Yon  Baer,  although  he  held  the  doctrine 
of  Epigeuesis,  coupled  it,  as  many  others  have  done,  with 
metapliysical  doctrines  to  which  it  is  radically  opposed. 
He  believed  in  Types  as  realities ;  he  was  therefore  con- 
sistent in  saying,  "  It  is  not  the  Matter  and  its  arrange- 
ments which  determine  the  product,  but  the  nature  of  the 
parent  form  —  the  Idea,  according  to  the  new  school." 
How  are  we  to  understand  this  Idea  ?  If  it  mean  an 
independent  Entity,  an  agency  external  to  the  organism, 
we  refuse  to  acknowledge  its  existence.  If  it  mean  only 
an  a  posteriori  abstraction  expressing  the  totality  of  the 
conditions,  then,  indeed,  we  acknowledge  that  it  deter- 
mines the  animal  form ;  but  this  is  only  an  abbreviated 
way  of  expressing  the  law  of  Evolution,  by  which  each 
stage  determines  its  successor.  The  Type  does  not  dom- 
inate the  conditions,  it  emerges  from  them  ;  the  animal 
organism  is  not  cast  in  a  mould,  but  the  imaginary  mould 
is  the  form  which  the  polarities  of  the  organic  substance 
assume.  It  would  seem  very  absurd  to  suppose  that  crys- 
tals assumed  their  definite  shapes  (when  the  liquid  which 
held  their  molecules  in  solution  is  evaporated)  under  the 
determining  impulse  of  phantom- crystals,  or  Ideas ;  yet 
it  has  not  been  thought  absurd  to  assume  phantom  forms 
of  organisms. 

112.  The  conception  of  Type  as  a  determining  influ- 
ence arises  from  that  fallacy  of  taking  a  resultant  for  a 
principle,  which  has  played  so  conspicuous  a  part  in  the 
history  of  philosophy.  Like  many  others  of  its  class  it 
exhibits  an   interesting  evolution  from  the  crude   meta- 


THE   NATURE   OF  LIFE. 

physical  to  the  subtle  metaphysical  point  of  view,  which 
at  last  insensibly  blends  into  the  positive  point  of  view. 
At  first  the  Type  or  Idea  was  regarded  as  an  objective 
reality,  external  to  the  organism  it  was  supposed  to  rule. 
Then  this  notion  was  replaced  by  an  approach  to  the 
more  rational  interpretation,  the  idea  was  made  an  inter- 
nal not  an  external  force,  and  was  incorporated  with  the 
material  elements  of  the  organism,  which  were  said  to 
"  endeavor  "  to  arrange  themselves  according  to  the  Type. 
Thus  Treviranus  declares  that  the  seed  "dreams  of  the 
future  flower";  and  "Henle,  when  he  affirms  that  hair 
and  nails  grow  in  virtue  of  the  Idea,  is  forced  to  add  that 
the  parts  endeavor  to  arrange  themselves  according  to 
this  Idea."  *  Even  Lotze,  who  has  argued  so  victoriously 
against  the  vitalists,  and  has  made  it  clear  that  an  organ- 
ism is  a  vital  mechanism,  cannot  relinquish  this  con- 
ception of  legislative  Ideas,  though  he  significantly  adds, 
"  these  have  no  power  in  themselves,  but  only  in  as  far 
as  they  are  grounded  in  mechanical  conditions."  Why 
then  superfluously  add  them  to  the  conditions  ?  If  every 
part  of  a  watch,  in  virtue  of  the  properties  inherent  in 
its  substance,  and  of  the  mutual  reactions  of  these  and 
otlier  parts,  has  a  mechanical  value,  and  if  the  sum  of 
all  these  parts  is  tlie  time-indicating  mechanism,  do  we 
add  to  our  knowledge  of  the  watch,  and  our  means  of 
repairing  or  improving  it,  by  assuming  that  the  parts 
have  over  and  above  their  physical  properties  the  meta- 
])hysical  "  tendency  "  or  "  desire  "  to  arrange  themselves 
into  this  specific  form?  When  we  see  that  an  organism 
is  constructed  of  various  parts,  each  of  which  has  its  own 
properties  inalienable  from  its  structure,  and  its  uses 
dependent  on  its  relation  to  other  parts,  do  we  gain  any 
larger  insight  by  crediting  these  parts   witli  desires   or 

*  Lotze,  art.  Lcbcnskraft,  in  Wagner's  Uandwortcrhucli,  (kr  Physiolo- 
(jic,  p.  XXVL 


108  THE  niYsiCAL  basis  of  mind. 

"dreams"  of  a  future  result  which  their  union  will 
effect  ?  That  which  is  true  in  this  conception  of  legis- 
lative Ideas  is  that  when  the  parts  come  together  there 
is  mutual  reaction,  and  the  resultant  of  the  wliole  is 
something  very  unlike  the  mere  addition  of  the  items, 
just  as  water  is  very  unlike  oxygen  or  hydrogen;  fur- 
ther, the  connexus  of  the  whole  impresses  a  peculiar 
direction  on  the  development  of  the  parts,  and  the  law 
of  Epigenesis  necessitates  a  serial  development,  which 
may  easily  be  interpreted  as  due  to  a  preordained 
plan. 

113.  In  a  word,  this  conception  of  T}^De  only  adds  a 
new  name  to  the  old  difficulty,  adding  mist  to  darkness. 
The  law  of  Epigenesis,  which  is  simply  the  expression  of 
the  material  process  determined  by  the  polarity  of  mole- 
cules, explains  as  much  of  the  phenomena  as  is  explica- 
ble. A  lost  limb  is  replaced  by  the  very  processes,  and 
through  the  same  progressive  stages  as  those  which  origi- 
nally produced  it.  We  have  a  demonstration  of  its  not 
being  reformed  according  to  any  Idea  or  Type  which 
exists  apart  from  the  immanent  properties  of  the  organic 
molecules,  in  the  fact  that  it  is  not  reformed  at  once,  but 
by  gradual  evolution ;  the  mass  of  cells  at  the  stump  are 
cells  of  embryonic  character,  cells  such  as  those  whicli 
originally  "crystallized"  into  muscles,  nerves,  vessels, 
and  integument,  and  each  cell  passes  through  all  its  or- 
dinary stages  of  development.  It  is  to  be  remembered 
that  so  intimately  dependent  is  tlie  result  on  the  deter- 
mining conditions,  that  any  external  influence  which 
disturbs  the  normal  course  of  development  will  either 
produce  an  anomaly,  or  frustrate  the  formation  of  a  new 
limb  altogether.  One  of  my  tritons  bit  off  the  leg  of  his 
female ;  *  the  leg  which  replaced  it  was  much  malformed, 

*  I  had  kept  these  tritons  four  years  in  the  hope  that  they  wouLl 
breed ;  but  in  spite  of  their  being  subjected  to  great  varieties  of  treat- 


THE   NATURE   OF   LIFE.  109 

and  curled  over  the  back  so  as  to  be  useless ;  was  this 
according  to  the  Idea  ?  I  cut  it  off,  and  examined  it ; 
all  the  bones  were  present,  but  the  humerus  was  twisted, 
and  of  small  size.  In  a  few  weeks  a  new  leg  was  de- 
veloped, and  this  leg  was  normal.  If  the  Idea,  as  a  rul- 
ing power,  determined  the  growth  of  this  third  leg,  what 
determined  the  second,  which  was  malformed  ?  Are  we 
to  suppose  that  in  normal  growth  the  Idea  prevails,  in 
abnormal  tlie  conditions  ?  That  it  is  the  polarity  of  the 
molecules  which  at  each  moment  determines  the  group 
those  molecules  will  assume,  is  well  seen  in  the  experi- 
ment of  Lavalle  mentioned  by  Bronn.*  He  showed  that 
if  when  an  octohedral  crystal  is  forming,  an  angle  be  cut 
away,  so  as  to  produce  an  artificial  surface,  a  similar 
surface  is  produced  spontaneously  on  the  corresponding 
angle,  whereas  all  the  other  angles  are  sharply  defined. 
"  Valentin,"  says  Mr.  Darwin,  "  injured  the  caudal  ex- 
tremity of  an  embryo,  and  three  days  afterwards  it  pro- 
duced rudiments  of  a  double  pelvis,  and  of  double  hind 
limbs.  Hunter  and  others  have  observed  lizards  with 
their  tails  reproduced  and  doubled.  When  Bonnet  di- 
vided longitudinally  the  foot  of  the  salamander,  several 
additional  digits  were  occasionally  formed."  f  Where  is 
the  evidence  of  the  Idea  in  these  cases  ? 

mcnt  —  for  month.s  well  .suiiplicd  with  food,  and  for  inoiitlis  reduced 
almost  to  starvation  —  they  never  showed  tlie  slightest  tendency  to 
breed  ;  another  among  the  many  illustrations  of  the  readiness  witli  which 
the  generative  system  is  affected  even  in  very  hardy  and  not  very  im- 
l)ressional)le  animals.  Ci.APAUkDE  observed  the  still  more  surprising 
fact  that  the  Ncrilina  fliivintilis  (a  river  snail)  not  only  will  not  lay 
egg.s,  but  will  not  even  feed  in  captivity.  lie  attributes  it  to  the  still- 
ness of  the  water  in  the  aquarium,  so  unlike  that  of  the  running  streams 
in  which  the  niolliLSC  lives.     See  Miillcr^n  Archiv,  IS.'i?. 

*  Br.ONN,  Morphnloffisclie  Studicn  ubcr  die  Gcslallung-Gesctze,  1858. 
Compare  the  note  on  §  11. 

t  Dai'vWin,  On  Domesticafioii,  II.  340.  In  the  Annalen  des  Sciences, 
1862,  p.  358,  M.  Malm  describes  a  fush  in  his  collection,  the  tail  of  which 


no  THE   PHYSICAL   BASIS   OF   MIND. 

114.  I  repeat,  the  reproduction  of  lost  limbs  is  due  to 
a  process  which  is  in  all  essential  respects  the  same  as 
that  which  originally  produced  them  ;  the  genesis  of  one 
group  of  cells  is  the  necessary  condition  for  the  genesis 
of  its  successor,  nor  can  this  order  be  transposed.  But  — 
and  the  point  is  very  important  —  it  is  not  every  part 
that  can  be  reproduced,  nor  is  it  every  animal  that  has 
reproductive  powers.  The  worm,  or  the  mollusc,  seems 
capable  of  reproducing  every  part ;  the  crab  will  repro- 
duce its  claws,  but  not  its  head  or  tail ;  the  perfect  insect 
of  the  higher  orders  will  reproduce  no  part  (indeed  the 
amputation  of  its  antennae  only  is  fatal),  the  salamander 
will  reproduce  its  leg,  the  frog  not.  In  human  beings  a 
muscle  is  said  never  to  be  reproduced ;  but  this  is  not  the 
case  in  the  rare  examples  of  supplementary  fingers  and  toes, 
which  have  been  known  to  grow  again  after  amputation. 
The  explanation  of  this  difference  in  the  reproductive 
powers  of  different  animals  is  usually  assigned  to  the  de- 
gree in  which  their  organisms  retain  the  embryonic  con- 
dition ;  and  this  explanation  is  made  plausible  by  the  fact 
that  the  animals  which  when  adult  have  no  power  of 
replacing  lost  limbs  have  the  power  when  in  the  larval 
state.  But  although  this  may  in  some  cases  be  the  true 
explanation,  there  are  many  in  which  it  fails,  as  will  be 
acknowledged  after  a  survey  of  the  extremely  various 
organisms  at  widely  different  parts  of  the  animal  series 
which  possess  the  reproductive  power.  Even  animals  in 
the  same  class,  and  at  the  same  stage  of  development,  dif- 
fer in  this  respect.  I  do  not  attach  much  importance  to 
the  fact  that  all  my  experiments  on  marine  annelids 
failed  to  furnish  evidence  of  their  power  of  reproducing 
lost  segments  ;  because  it  is  difficult  to  keep  them  under 
conditions  similar  to  those  in  which  they  live.     But  it  is 

had  been  broken,  and  the  bone  which  grew  out  at  the  injured  spot  had 
foniied  a  second  tail  with  terminal  fin. 


THE   NATURE   OF   LIFE.  Ill 

significant  that,  among  the  hundreds  which  have  passed 
under  my  observation,  not  one  should  have  been  found 
with  a  head-segment  in  the  process  of  development,  re- 
placing one  that  had  been  destroyed ;  and  this  is  all  the 
more  remarkable  from  the  great  tenacity  of  life  which  the 
mutilated  segments  manifest.  Quatrefages  had  observed 
portions  of  a  worm,  after  gangrene  had  destroyed  its  head 
and  several  segments,  move  about  in  the  water  and  avoid 
the  light !  * 

115.  A  final  argument  to  show  that  the  reproduction 
is  not  determined  by  any  ruling  Idea,  but  by  the  organic 
conditions  and  the  necessary  stages  of  evolution,  is  seen 
in  the  reappearance  of  a  tumor  or  cancer  after  it  has  been 
removed.  "We  find  the  new  tissue  appear  with  all  the 
characters  of  the  normal  tissue  of  the  gland,  then  rapidly 
assume  one  by  one  the  characters  of  the  diseased  tissue 
which  had  been  removed ;  and  there  as  on  is,  that  the  regen- 
eration of  the  tissue  is  accompanied  by  the  same  abnormal 
conditions  which  formerly  gave  rise  to  the  tumor:  the 
directions  of  "  crystallization  "  are  similar  because  the  con- 
ditions are  similar.  In  every  case  of  growth  or  regrowth 
the  conditions  being  the  same,  the  result  must  be  the  same. 

*  In  the  memoir  on  the  Anafomi/  and  PhysioJog;;  nf  the  Nematoids,  by 
Dr.  Charlton  Bastian,  which  appeared  in  tlie  Philosophical  Transac- 
lions  for  1866,  we  read  that  even  these  lowly  organized  worms  have  little 
power  of  repair.  Speaking  of  the  "paste  eels"  {AnijuiluUda;),  he  says, 
"  I  may  state  as  the  result  of  many  experiments  with  these  that  the 
power  they  possess  of  repairing  injuries  seems  very  low.  I  have  cut  off 
portions  of  the  posterior  extremity,  and  though  I  watched  the  animal 
for  days  after,  could  never  recognize  an j' attempt  at  rc])air."  Perhaps, 
iiowever,  the  season  may  have  some  influence  ;  and  Dr.  Wilmams's 
denial  respecting  the  Nais  may  be  thus  explained.  [What  is  said  above 
was  written  in  1868,  and  imblishcdin  the  .Tune  number  of  the  Fortnir/kt.h/ 
Review.  In  the  August  of  tliat  year  the  question  of  7'eproduetion  of  lost 
limbs  was  treated  by  Prof.  Rolm:kton  in  liis  Address  to  the  British  Medi- 
r.al  Association,  in  whidi  he  sliowed  cog(!nt  evidence  for  the  conclusion 
that  tlie  reproduction  of  limbs  only  exists  in  animals  that  have  feeble 
respiration,  and  consequently  slow  vital  processes.] 


112  THE   PHYSICAL   BASIS   OF   MIND. 

IIG.  It  seems  a  truism  to  insist  that  similarity  in  the 
results  must  he  due  to  similarity  in  the  conditions ;  yet 
it  is  one  which  many  theorists  disregard ;  and  especially 
do  we  need  to  hear  it  in  mind  Avhen  arguing  ahout  Spe- 
cies. I  will  here  only  touch  on  the  suggestive  topic  of 
the  analogies  observed  not  simply  among  animals  at  the 
extreme  ends  of  the  scale,  but  also  between  animals  and 
plants  where  the  idea  of  a  direct  kinshiji  is  out  of  the 
question. 

My  very  imperfect  zoological  knowledge  will  not  allow 
me  to  adduce  a  long  array  of  instances,  but  such  an  array 
will  assuredly  occur  to  every  well-stored  mind.  It  is 
enough  to  point  to  the  many  analogies  of  Function,  more 
especially  in  the  reproductive  processes  —  to  the  exist- 
ence of  burrowers,  waders,  flyers,  swimmers  in  various 
classes  —  to  the  existence  of  predatory  mammals,  preda- 
tory birds,  predatory  reptiles,  predatory  insects  by  the  side 
of  herbivorous  congeners,  — -  to  the  nest-building  and 
incubating  fishes  ;  and  in  the  matter  of  Structure  the 
analogies  are  even  more  illustrative  when  we  consider 
the  widely  diffused  spicula,  seise,  spines,  books,  tentacles, 
beaks,  feathery  forms,  nettling-organs,  poison-sacs,  lumi- 
nous organs,  etc.  ;  because  these  have  the  obvious  impress 
of  being  due  to  a  community  of  substance  under  similar 
conditions  rather  than  to  a  community  of  kinship.  The 
beak  of  the  tadpole,  the  cephalopod,  the  male  salmon,  and 
the  bird,  are  no  doubt  in  many  respects  unlike  ;  but  there 
is  a  significant  likeness  among  them,  which  constitutes  a 
true  analogy.  I  think  there  is  such  an  analogy  between 
the  air-bladder  of  fishes  and  the  tracheal  rudiment  which 
is  found  in  the  gnat-larva  (Coixihra  plumico7mis).*     Very 

*  This  beautiful  and  transparent  larva  reminds  one  in  many  respects 
of  the  Pike  as  it  poises  itself  in  the  water  awaiting  its  prey.  It  is  en- 
abled to  do  so  without  the  slightest  exertion  by  the  air-bladders  which 
it  possesses  in  the  two  kidney-shaped  rudiments  of  trachese,  and  which 


THE   NATURE   OF   LIFE.  113 

remarkable  also  is  the  resemblance  of  the  avicularium, 
or  "  bird's-head  process,"  on  the  polyzoon  known  popu- 
larly as  the  Corkscrew  Coralline  {Bagula  avicularia), 
which  presents  us  in  miniature  with  a  vulture's  head  — 
two  mandibles,  one  fixed,  the  other  moved  by  muscles 
\isible  within  the  head.  No  one  can  watch  this  organ 
snapping  incessantly,  without  being  reminded  of  a  vul- 
ture, yet  no  one  would  suppose  for  a  moment  that  the 
resemblance  has  anything  to  do  with  kinship. 

117.  Such  cases  are  commonly  robbed  of  their  due 
significance  by  being  dismissed  as  coincidences.  But 
what  determines  the  coincidence  ?  If  we  assume,  as  we 
are  justified  in  assuming,  that  the  possible  directions  of 
Organic  Combination,  and  the  resultant  forms,  are  lim- 
ited, there  must  inevitably  occur  such  coincident  lines : 
the  hooks  on  a  Climbing  Plant  will  resemble  the  hooks 
on  a  Crustacean  or  the  claws  of  a  Bird,  as  the  one  form 
iu  which  under  similar  external  forces  the  more  solid  but 
not  massive  portions  of  the  integument  tend  to  develop. 
I  am  too  ill  acquainted  with  the  anatomy  of  plants  to  say 
liow  the  hooks  so  common  among  them  arise ;  but  from 
examination  of  the  Blackberry,  and  comparison  of  its 
tliorns  with  the  hooks  and  spines  of  the  Crustacea,  I  am 
led  to  infer  that  in  each  case  the  mode  of  development 
is  identical  —  namely,  the  secretion  of  chitine  from  the 
cellular  matrix  of  the  integument. 

in  the  gnat  become  developed  into  the  respiratory  apparatus.  The 
resemblance  to  the  air-bladder  of  fishes  is  not  simply  that  it  serves  a 
similar  purpose  of  sustaining  the  body  in  the  water,  it  is  in  both 
(•a.ses  a  rudiment  of  the  respiratory  apparatus,  which  in  the  fish  never 
becomes  developed.  Wki.smann  calls  attention  to  an  organ  in  the  larvaj 
of  certain  insects  (the  CulirAdoe),  Avhicli  have  what  he  calls  a  tracheal 
ijill,  whi(di  gill  lias  this  striking  analogy  with  the  fish-gill  that  it  sepa- 
rates the  air  from  the  water,  and  not,  as  a  trachea,  direct  from  the  atmos- 
phere. See  his  remarkable  memoir  Die  nachcmhrynnah  En/imckcbiii{j 
d'-.s  Muscidens,  in  Siebold  uvd  KoUiker'.i  Znlschrift,  1864,  p.  223. 


114  THE  PHYSICAL  BASIS   OF  JIIXD. 

Another  mode  of  evading  the  real  significance  of  such 
resemblances  is  to  call  them  analogies,  not  homologies. 
There  is  an  advantage  in  having  two  such  terms,  but  we 
ought  to  be  very  clear  as  to  their  meaning  and  their  point 
of  separation.  Analogy  is  used  to  designate  similarity  in 
Function  with  dissimilarity  in  Structure.  The  wing  of 
an  insect,  the  wing  of  a  bird,  and  the  wing  of  a  bat  are 
called  analogous,  but  not  homologous,  because  their  ana- 
tomical structure  is  different :  they  are  not  constructed 
out  of  similar  anatomical  parts.  The  fore-leg  of  a  mam- 
mal, the  wing  of  a  bird,  or  the  paddle  of  a  whale,  are 
called  homologous,  because  in  spite  of  their  diverse  uses 
they  are  constructed  out  of  corresponding  anatomical 
parts.  To  the  anatomist  such  distinctions  are  eminently 
serviceable.  But  they  have  led  to  some  misconceptions, 
because  they  are  connected  with  a  profound  misconcep- 
tion of  the  relation  between  Function  and  Organ.  Em- 
bryology teaches  that  the  wing  of  the  bird  and  the  paddle 
of  the  whale  are  developed  out  of  corresponding  parts, 
and  that  these  are  not  like  the  parts  from  which  the  wing 
of  an  insect  or  the  flying-fish  will  be  developed ;  never- 
theless, the  most  cursory  inspection  reveals  that  the  wing 
of  a  bird  and  the  paddle  of  a  whale  are  very  unlike  in 
structure  no  less  than  in  function,  and  that  their  diversi- 
ties in  function  correspond  with  tlieir  diversities  in  struc- 
ture ;  whereas  the  wing  of  the  insect,  of  the  bird,  and  of 
the  bat,  are  in  certain  characters  very  similar,  and  corre- 
spondingly there  are  similarities  in  their  function.  It  is, 
however,  obvious  that  the  resemblance  in  function  is 
strictly  limited  to  the  resemblance  in  anatomical  struc- 
ture ;  only  in  loose  ordinary  speech  can  the  flight  of  an 
insect,  a  bird,  or  a  bat  be  said  to  be  "  the  same  "  :  it  is  dif- 
ferent in  each  — the  weight  to  be  moved,  the  rapidity  of 
the  movement,  the  precision  of  the  movements,  and  their 
endurance,  all  differ. 


THE   NATURE   OF   LIFE.  115 


NATURAL   SELECTION   AND   ORGANIC   AFFINITY. 

118.  It  is  impossible  to  treat  of  Evolution  without 
taking  notice  of  that  luminous  hypothesis  by  which  Mr. 
Darwin  has  revolutionized  Zoology.  There  are  two  points 
needful  to  be  clearly  apprehended  before  the  question  is 
entered  upon.  The  first  point  relates  to  the  lax  use  of 
the  phrase  "  conditions,"  sometimes  more  instructively 
replaced  l)y  "  conditions  of  existence."  Inasmuch  as  Life 
is  only  jiossible  under  definite  relations  of  the  organism 
and  its  medium,  the  "  conditions  of  existence "  M'ill  be 
those  physical,  chemical,  and  physiological  changes,  which 
in  the  organism,  and  out  of  it,  co-operate  to  produce  the 
result.  There  are  myriads  of  changes  in  the  external 
medium  which  have  no  corresponding  changes  in  the 
organism,  not  being  in  any  direct  relation  to  it  (see  §  54). 
These,  not  being  co-operant  conditions,  must  be  left  out 
of  the  account ;  they  are  not  conditions  of  existence  for 
the  organism,  and  therefore  the  organism  does  not  vary 
with  their  variations.  On  the  other  hand,  what  seem 
very  slight  changes  in  the  medium  are  often  responded  to 
by  important  changes  in  the  vital  chemistry,  and  conse- 
quently in  the  structure  of  the  organism.  Now  the 
nature  of  the  organism  at  the  time  being,  that  is  to  say, 
its  structure  and  tlie  physico-chemical  state  of  its  tissues 
and  plasmodes,  is  the  main  condition  of  this  response; 
the  same  external  agent  will  be  powerful,  or  powerless, 
over  sliglitly  different  organisms,  or  over  the  same  organ- 
ism at  different  times.  Usually,  and  for  convenience, 
when  biologists  speak  of  conditions,  they  only  refer  to 
external  clianges.  This  usage  has  been  tlie  source  of  no 
little  confusion  in  discussing  tlie  Development  Hypoth- 
esis. Mr.  Darwin,  however,  while  following  the  estab- 
lished usage,  is  careful  in  several  places  to  declare  that 
of  the  two  factors  in  Variation  —  the  nature  of  the  or^an- 


116  THE  PHYSICAL  BASIS   OF  MIND. 

ism  and  the  nature  of  the  conditions  —  the  former  is  by 
far  the  more  important. 

llS^f.  A  still  greater  modification  of  terms  must  now 
be  made.  Instead  of  confining  the  "struggle  for  exist- 
ence "  to  the  competition  of  riv^als  and  the  antagonism 
of  foes,  we  must  extend  it  to  the  competition  and  an- 
tagonism of  tissues  and  organs.  The  existence  of  an 
organism  is  not  only  dependent  on  the  external  existence 
of  others,  and  is  the  outcome  of  a  struggle ;  but  also  on 
the  internal  conditions  which  co-operate  in  the  formation 
of  its  structure,  this,  structure  being  the  outcome  of  a 
struggle.  The  organism  is  this  'particular  organism,  dif- 
fering from  others,  because  of  the  particular  conditions 
which  have  co-operated.  The  primary  and  fundamental 
struggle  must  be  that  of  the  organic  forces  at  work  in 
creating  a  structure  capable  of  pushing  its  way  amid 
external  forces.  The  organism  must  find  a  footing  in  the 
world,  before  it  can  compete  with  rivals,  and  defend 
itself  against  foes.  Owing  to  the  power  of  reproduction, 
every  organism  has  a  potential  indefiniteuess  of  multi- 
plication ;  that  potential  indefiniteuess  is,  however,  in 
reality  restricted  by  the  supply  of  food,  and  by  the  com- 
petition of  rivals  for  that  supply.  The  multiplication 
of  any  one  species  is  thus  kept  down  by  the  presence  of 
rivals  and  foes :  a  balance  is  reached,  whicli  permits  of 
the  restricted  quantities  of  various  species.  This  balance 
is  the  result  of  a  struggle. 

Now  let  me  call  attention  to  a  similar  process  in  the 
formation  of  the  organism  itself.  Every  organite,  and 
every  tissue,  has  a  potential  growth  of  indefinite  extent, 
but  its  real  growth  is  rigorously  limited  by  the  compe- 
tition and  antagonism  of  the  others,  each  of  which  has 
its  potential  indefiniteness,  and  its  real  limits.  Some- 
thing, in  the  food  assimilated,  slightly  alters  the  part 
whicli  assimilates  it.     This  change  may  be  the  origin  of 


^THE   NATURE  OF  LIFE.  117 

other  changes  in  the  part  itself,  or  in  neighboring  parts, 
stimulating  or  arresting  the  vital  processes.  A  modifica- 
tion of  structure  results.  Or  there  may  be  no  new  sub- 
stance assimilated,  but  external  forces  may  call  a  part 
into  increased  activity  —  which  means  increased  waste 
and  repair;  and  this  increase  here  is  the  cause  of  a 
corresponding  decrease  somewhere  else.  Whatever  the 
nature  of  the  change,  it  finds  its  place  amid  a  complex 
of  changes,  and  its  results  are  compounded  with  theirs. 
When  organites  and  tissues  are  said  to  have  a  potential 
indefiniteness  of  growth,  there  is  assumed  a  potential 
indefiniteness  in  the  pabulum  supplied :  if  the  pabulum 
were  supplied,  and  if  there  were  no  antagonism  thwart- 
ing its  assimilation,  growth  would  of  course  continue 
without  pause,  or  end ;  but  in  reality  this  cannot  be  so. 
For,  take  the  blood  as  the  vehicle  of  the  pabulum  —  not 
only  is  its  quantity  limited,  and  partly  limited  by  the 
very  action  of  the  tissues  it  feeds,  but  even  in  any  given 
quantity  there  is  a  limit  to  its  composition  —  it  will  only 
take  up  a  limited  quantity  of  salts,  iron,  albumen,  etc. ; 
no  matter  how  abundant  these  may  be  in  the  food.  So 
again  with  the  plasmodes  of  the  various  tissues  —  they 
have  eacli  their  definite  capacities  of  assimilation.  AVhat 
has  already  been  stated  respecting  chemical  affinity  (§  20) 
is  equally  applicable  to  organic  affinity ;  as  the  presence 
of  fused  iron  in  the  crucible  partially  obstructs  the  com- 
l)ination  of  sulphur  and  lead,  so  the  presence  of  connec- 
tive tissue  pai'tially  obstructs  the  combination  of  nmscle 
protoplasm  witli  its  pal)ulum. 

118  b.  Owing  to  the  action  and  reaction  of  blood  and 
])lasmode,  of  tissues  on  tissues,  and  organs  on  organs, 
and  their  mutual  limitations,  the  growtli  of  each  organ- 
ism has  a  limit,  and  the  growth  of  each  organ  has  a  limit. 
IJeyond  this  limit,  no  extra  supply  of  food  will  increase 
the  size  of  the  organism;  no  increase  of  activity  will 


118  THE   niYSICAL   BASIS   OF   MIND. 

increase  tlie  organ.  "  Man  cannot  add  a  cubit  to  his 
stature."  The  blacksmith's  arm  will  not  grow  larger  by- 
twenty  years  of  daily  exercise,  after  it  has  once  attained 
a  certain  size.  Increase  of  activity  caused  it  to  enlarge 
up  to  this  limit ;  but  no  increase  of  activity  will  cause  it 
to  pass  this  limit.  Why  ?  Because  here  a  balance  of  the 
co-operating  formative  forces  has  been  reached.  Larger 
muscles,  or  more  muscle-fibres,  demand  arteries  of  larger 
calibre,  and  these  a  heart  of  larger  size ;  with  the  increase 
of  muscle  would  come  increase  of  connective  tissue ;  and 
this  tissue  would  not  only  compete  with  the  muscle  for 
pabulum,  but  by  mechanical  pressure  would  diminish  the 
flow  of  that  pabulum.  And  why  would  connective  tissue 
increase  ?  Because,  in  the  first  place,  there  is  a  forma- 
tive association  between  the  two,  so  that  owing  to  a  law, 
not  yet  understood,  the  one  always  accompanies  the 
other ;  and,  in  the  second  place,  there  is  a  functional  as- 
sociation between  the  two,  a  muscle-fibre  being  inopeirt- 
iive  unless  it  be  attached  to  a  tendon,  or  connective 
tissue ;  it  will  contract  out  of  the  body  although  sepa- 
rated from  its  tendon  or  other  attachment ;  but  in  the 
body  its  contraction  would  be  useless  without  this  attach- 
ment. We  must  bear  in  mind  that  muscle-fibres  are 
very  much  shorter  than  ordinary  muscles ;  according  to 
the  measurements  of  W.  Krause  they  never  exceed  4  cm 
in  length,  and  usually  range  between  2  and  3  cm ;  their 
fine  points  being  fixed  to  the  interstitial  connective  tissue, 
as  the  whole  muscle  is  fixed  to  its  tendon.  The  functibn 
of  the  muscle  is  thus  dependent  on  a  due  balance  of  its 
component  tissues ;  if  that  balance  is  disturbed  the  func- 
tion is  disturbed.  Should,  from  any  cause,  an  excess  of 
muscle-fibre  arise,  the  balance  would  be  disturbed  ;  should 
an  encroachment  of  connective  tissue,  or  of  fat,  take 
place,  there  would  be  also  a  defect  of  function. 

Here  we  have  the  co-operation  and  limitation  of  the 


THE   NATUEE   OF   LIFE.  119 

tissues  illustrated ;  let  us  extend  our  glance,  and  we  shall 
see  how  the  co-operation  and  limitation  of  the  organs 
come  into  play,  so  that  the  resulting  function  depends  on 
the  balance  of  their  forces.  The  contractile  power  of 
each  individual  muscle  is  always  limited  by  the  resistance 
of  antagonists,  which  prevent  the  muscle  being  contracted 
more  than  about  a  tliird  of  its  2'>ossihle  extent,  i.  e.  possi- 
ble when  there  are  no  resistances  to  be  overcome.  Not 
only  the  increasing  tension  of  antagonist  muscles,  but  the 
resistance  of  tendons,  bones,  and  softer  parts  must  be 
taken  into  account.  Thus,  the  increase  of  the  black- 
smith's muscular  power  would  involve  a  considerable  in- 
crease in  all  the  tissues  of  tlie  arm  ;  but  such  an  increase 
would  involve  a  reconstruction  of  his  whole  organism. 

Whenever  there  is  an  encroachment  of  one  tissue  on 
another,  there  is  a  disturbance  of  the  normal  balance, 
which  readily  passes  into  a  pathological  state.  If  the 
brain  is  overrun  with  connective  tissue,  or  the  heart  with 
fatty  tissue,  we  know  the  consequences.  If  connective 
tissue  is  deficient,  epithelial  runs  to  excess,  no  longer  lim- 
ited by  its  normal  antagonist,  and  pus,  or  cancer,  result. 

118  c.  It  is  unnecessary  here  to  enlarge  on  this  point, 
I  have  adduced  it  to  show  tliat  we  must  extend  our  con- 
ception of  the  struggle  for  existence  beyond  that  of  the 
competition  and  antagonism  of  organisms  —  the  external 
struggle  ;  and  include  under  it  the  competition  and  antag- 
onism of  tissues  and  organs  —  the  internal  struggle.  Va- 
riability is  inherent  in  organic  substances,  as  the  result 
of  their  indefiniteness  of  composition  (§  45?>).  Tliis  vari- 
ability is  indefinite,  and  is  rendered  definite  by  the  com- 
petition and  antagonism,  so  that  every  particular  variation 
is  the  resultant  of  a  composition  of  forces.  The  forces  in 
operation  are  the  internal  and  external  conditions  of  ex- 
istence —  i.  e.  the  nature  of  the  organism,  and  its  response 
to  the  actions  of  its  mediunj.     A  cliange  may  take  place 


120  THE   PHYSICAL   BASIS   OF   MIND. 

in  UiG  niedimii  witliout  a  corresponding  response  from  the 
organism ;  or  the  change  may  find  a  response  and  the 
organism  become  modified.  Every  modification  is  a  selec- 
tion, determined  by  laws  of  growth  ;  it  is  the  resultant 
of  a  struggle  between  what,  for  want  of  a  better  term, 
may  be  called  the  organic  affinities  —  which  rej)resent  in 
organized  substances  what  chemical  affinities  are  in  the 
anorganized.  Just  as  an  organism  which  has  been  modi- 
fied and  thereby  gained  a  superiority  over  others,  has  by 
this  modification  been  selected  for  survival  —  the  selection 
being  only  another  aspeqt  of  this  modification  —  so  one 
tissue,  or  one  organ,  which  has  surpassed  another  in  the 
struggle  of  growth,  will  thereby  have  become  selected. 
Natural  Selection,  or  survival  of  the  fittest,  therefore,  is 
simply  the  metaphorical  expression  of  the  fact  that  any 
balance  of  the  forces  which  is  best  adapted  for  survival 
wHl  survive.  Unless  we  interpret  it  as  a  shorthand  ex- 
pression of  all  the  internal  and  external  conditions  of 
existence,  it  is  not  acceptable  as  the  origin  of  species. 

118  (i.  Mr.  Darwin  has  so  patiently  and  profoundly 
meditated  on  the  whole  subject,  that  we  must  be  very 
slow  in  presuming  him  to  have  overlooked  any  important 
point.  I  kuow^  that  he  has  not  altogether  overlooked  this 
which  we  are  now  considering ;  but  he  is  so  preoccupied 
with  the  tracing  out  of  his  splendid  discovery  in  all  its 
bearings,  that  lie  has  thrown  the  emphasis  mainly  on  the 
external  struggle,  neglecting  the  internal  struggle  ;  and  has 
thus  in  many  passages  employed  language  which  implies 
a  radical  distinction  where  —  as  I  conceive  —  no  such 
distinction  can  be  recognized.  "Natural  Selection,"  he 
says,  "  depends  on  the  survival  under  various  and  complex 
circumstances  of  the  best-fitted  individuals,  but  has  no 
relation  whatever  to  the  primary  cause  of  any  modifica- 
tion of  structure."  *     On  this  we  may  remark,  first,  that 

*  The  Variation  of  Aniiwds  and  Plants,  1868,  II.  p.  272. 


THE  NATURE   OF  LIFE.  121 

selection  does  not  depend  on  the  survival,  but  is  that  sur- 
vival;  secondly,  that  the  best-fitted  individual  survives 
because  of  that  modification  of  its  structure  which  has 
given  it  the  superiority ;  therefore  if  the  primary  cause 
of  this  modification  is  not  due  to  selection,  then  selection 
cannot  be  the  cause  of  species.  He  separates  Natural 
Selection  from  all  the  primary  causes  of  variation,  either 
internal  or  external  ■ —  either  as  results  of  the  laws  of 
growth,  of  the  correlations  of  variation,  of  use  and  disuse, 
etc.,  and  limits  it  to  the  slow  accumulations  of  such  vari- 
ations as  are  profitable  in  the  struggle  with  competitors. 
And  for  his  purpose  this  separation  is  necessary.  But 
biological  philosophy  must,  I  think,  regard  the  distinction 
as  artificial,  referring  only  to  one  of  the  great  factors  in 
the  production  of  species.  And  for  this  reason :  Selec- 
tion only  comes  into  existence  in  the  modifications  pro- 
duced either  by'  external  or  internal  clianges ;  and  the 
selected  change  cannot  be  developed  further  by  mere 
inheritance,  unless  the  successive  progeny  have  such  a 
disposition  of  the  organic  affinities  as  will  rej)eat  the  pri- 
mary change.  Inherited  superiority  will  not  by  mere 
transmission  become  greater.  The  facts  which  are  relied 
on  in  support  of  the  idea  of  "  fixity  of  species  "  show  at 
any  rate  that  a  given  superiority  will  remain  stationary 
for  thousands  of  years ;  and  no  one  supposes  that  tlie 
progeny  of  an  organism  will  vary  unless  some  external 
or  internal  cause  of  variation  accompanies  the  inheritance. 
Mr.  Darwin  agrees  with  Mr.  Spencer  in  admitting  the  dif- 
ficulty of  distinguishing  between  the  effects  of  some 
definite  action  of  external  conditions,  and  the  accumula- 
tion through  natural  selection  of  inherited  variations 
serviceaV)lo  to  the  organism.  But  even  in  cases  where 
the  di.stinction  could  be  clearly  established,  I  think  we 
should  only  sec  an  historiral  distinction,  that  is  to  say, 
one  between  effects  produced  by  particular  causes  now 

VOL.   HI.  6 


122  THE   PHYSICAL   BASIS   OF   MIND. 

in  operation,  and  effects  produced  by  very  complex  and 
obscure  causes  in  operation  during  ancestral  develop- 
ment. 

118  e.  The  reader  will  understand  that  my  criticism 
does  not  pretend  to  invalidate  Mr.  Darwin's  discovery, 
but  rather  to  enlarge  its  terms,  so  as  to  make  it  include 
all  the  biological  conditions,  and  thus  explain  many  of 
the  variations  which  Natural  Selection  —  in  the  restricted 
acceptation  —  leaves  out  of  account.  Mr.  Darwin  draws 
a  broad  line  of  distinction  between  Variation  and  Selec- 
tion, regarding  only  those  variations  that  are  favorable  as 
selected.  I  conceive  that  all  variations  which  survive  are 
by  tliat  fact  of  survival,  selections,  whether  favorable  or 
indifferent.  A  variety  is  a  species  in  formation ;  now 
Selection  itself  is  not  a  cause,  or  condition,  of  variation, 
it  is  the  expression  of  variation.  Mr.  Darwin  is  at  times 
explicit  enough  on  this  head  :  "  It  may  metaphorically  be 
said  tliat  Natural  Selection  is  daily  and  hourly  scrutiniz- 
ing throughout  the  world  the  slightest  variations ;  rejecting 
those  tliat  are  bad,  preserving  and  adding  up  all  that  are 
good ;  silently  and  insensibly  working,  whenever  and 
wherever  opportunity  offers,  at  tlie  improvement  of  each 
organic  being  in  relation  to  its  organic  and  inorganic  con- 
ditions of  life."*  But  the  metaphorical  nature  of  the 
term  is  not  always  borne  in  mind,  so  that  elsewhere 
Natural  Selection  is  said  to  "  act  on  and  modify  organic 
beings,"  as  if  it  were  a  positive  condition  and  not  the 
expression  of  the  modifying  processes.  Because  grouse 
are  largely  destroyed  by  birds  of  prey,  any  change  in  their 
color  which  would  render  them  less  conspicuous  would 
enable  more  birds  to  escape ;  but  it  is  obvious  that  this 
change  of  color  will  be  due  to  Organic  Affinity ;  and  only 
when  the  change  is  effected  will  there  have  been  that 
selection  which  exjjresses  it.     'Sh:  Darwin's  language,  how- 

*  Origin  of  SiKcies,  5tli  ed.  p.  96. 


THE  NATURE  OF  LIFE.  123 

ever,  is  misleading.  He  says  :  "  Hence  Natural  Selection 
might  be  most  effective  in  giving  the  proper  color  to  each 
kind  of  grouse,  and  in  keeping  that  color  when  once 
acquired."  This  is  to  make  Selection  an  agent,  a  condi- 
tion of  the  development  of  color ;  which  may  be  accepted 
if  we  extend  the  term  so  as  to  include  the  organic  changes 
themselves.  Again  :  "  Some  writers  have  imagined  that 
Natural  Selection  induces  variability,  whereas  it  only  im- 
plies the  2)reservation  of  such  variations  as  are  beneficial 
to  the  being  under  its  conditions  of  life."  It,  however,  is 
made  to  imply  more  than  this,  namely,  the  accumulation 
and  further  modification  of  such  variations.  "  The  mere 
existence  of  individual  variability  and  of  some  well- 
marked  varieties,  though  necessary  as  the  foundation, 
helps  us  but  little  in  understanding  how  species  arise  in 
nature.  How  have  all  those  exquisite  adaptations  of  one 
part  of  the  organization  to  another  part,  and  to  the  con- 
ditions of  life,  and  of  one  organic  being  to  another  being, 
been  perfected  ? "  ]\Iy  answer  to  this  question  would  be  : 
By  Organic  Affinity,  and  the  resulting  struggle  of  the  tis- 
sues and  organs,  the  consequences  of  which  are  tliat  very 
adaptation  of  the  organism  to  external  conditions,  which 
is  expressed  as  the  selection  of  the  structures  best  adapted. 
The  selections  are  the  results  of  the  struggle,  according 
to  my  proposed  extension  of  the  term  "  struggle."  Mr. 
Darwin  defines  the  struggle :  "  The  dependence  of  one 
being  on  another,  and  including  (what  is  more  important) 
not  only  the  life  of  the  individual  but  success  in  leaving 
progeny."  This  definition  seems  defective,  since  it  omits 
the  primary  and  more  important  struggle  wliicli  takes 
place  between  the  organic  affinities  in  operation.  To  suc- 
ceed in  the  struggle  with  competitors,  the  organism  must 
have  first  acquired  —  by  selection  —  a  su])eriority  in  one 
or  more  of  its  organs. 

118/.   A  little  reflection  will  disclose  the  importance 


124  THE  PHYSICAL  BASIS   OF  MIND. 

of  keeping  our  eyes  fixed  on  the  internal  causes  of  varia- 
tion, as  well  as  on  the  external  conditions  of  the  struggle. 
Mr.  Darwin  seems  to  imply  that  the  external  conditions 
which  cause  a  variation  are  to  be  distinguished  from  the 
conditions  which  accumulate  and  perfect  such  variation, 
that  is  to  say,  he  implies  a  radical  difference  between  the 
process  of  variation  and  the  process  of  selection.  This,  I 
have  already  said,  does  not  seem  to  me  acceptable ;  the 
selection,  I  conceive,  to  be  simply  the  variation  which 
has  survived.* 

If  it  be  true  that  a  Variety  is  an  incipient  Species  and 
shows  us  Species  in  formation,  it  is  in  the  same  sense 
true  that  a  variation  is  an  incipient  organ.  A  species  is 
the  result  of  a  slowly  accumulating  divergence  of  struc- 
ture; an  organ  is  the  result  of  a  slowly  accumulating 
differentiation.  At  each  stage  of  differentiation  there  has 
been  a  selection,  but  we  cannot  by  any  means  say  that 
this  selection  was  determined  by  the  fact  of  its  giving  the 
organism  a  superiority  over  rivals,  inasmuch  as  during  all 
the  early  stages,  while  the  organ  was  still  in  formation, 
there  could  be  no  advantage  accruing  from  it.  One  ani- 
mal having  teeth  and  claws  developed  will  have  a  decided 
superiority  in  the  struggle  over  another  animal  that  has 
no  teeth  and  claws ;  but  so  long  as  the  teeth  and  claws 
are  in  an  undeveloped  state  of  mere  preparation  they 
confer  no  superiority. 

118//.    Natural  Selection  is  only  the  expression  of  the 

*  Mr.  Darwin  has  himself,  iu  the  following  passage,  stated  a  somewhat 
similar  view,  and  rejected  it :  "In  one  sense  the  conditions  of  life  may 
be  said  not  only  to  cause  variability,  but  likewise  to  include  Natural 
Selection,  for  the  ccmditions  determine  whether  this  or  that  variety  shall 
survive.  But  when  man  is  the  selecting  agent,  we  clearly  see  that  the 
two  elements  of  change  are  distinct ;  the  conditions  cause  the  variability, 
the  will  of  man  acting  either  consciously  or  unconsciously  accumulates 
the  variations  in  certain  directions,  and  this  answers  to  the  survival  of 
the  fittest  under  nature."   (p.  168.) 


THE  NATURE   OF  LIFE.  125 

results  of  obscure  physiological  processes ;  and  for  a  satis- 
factory theory  of  such  results  we  must  understand  the 
nature  of  the  processes.  In  other  words,  to  understand 
Natural  Selection  we  must  recognize  not  only  the  facts 
tlius  expressed,  but  the  factors  of  these  facts,  —  we  must 
analyze  the  "  conditions  of  existence."  As  a  preliminary 
analysis  we  find  external  conditions,  among  which  are  in- 
cluded not  only  the  dependence  of  the  organism  on  the 
inorganic  medium,  but  also  the  dependence  of  one  organ- 
ism on  another,  —  the  competition  and  antagonism  of  the 
whole  organic  world;  and  internal  conditions,  among  which 
are  included  not  only  the  dependence  of  the  organism  on 
the  laws  of  composition  and  decomposition  whereby  each 
organite  and  each  tissue  is  formed,  but  also  the  depend- 
ence of  one  organite  and  one  tissue  on  all  the  others  — 
the  competition  and  antagonism  of  all  the  elements. 

The  changes  wrought  in  an  organism  by  these  two 
kinds  of  conditions  determine  Varieties  and  Species.  Al- 
though many  of  the  changes  are  due  to  the  process  of 
natural  selection  brought  about  in  the  struggle  witli  com- 
petitors and  foes,  many  other  changes  have  no  such  rela- 
tion to  the  external  struggle,  but  are  simply  tlie  results 
of  the  organic  affinities.  They  may  or  they  may  not  give 
the  organism  a  greater  stability,  or  a  greater  advantage 
over  rivals  ;  it  is  enougli  that  they  are  no  disadvantage 
to  the  organism,  they  will  then  survive  V)y  virtue  of  the 
forces  which  produced  them. 

119.  Tlie  position  tlius  readied  will  be  important  in 
our  examination  of  tlie  Theory  of  Descent  by  whicli  Mr. 
Darwin  tentatively,  and  liis  followers  boldly,  explain  the 
oljserved  resemblances  in  structure  and  function  as  due  to 
blood-relationship.  The  doctrine  of  Kvolution  allirins  that 
all  (^oiii]il(',x  organisms  are  evolved  by  differenlialidii  I'rora 
simpler  organisms,  as  we  see  the  complex  organ  (ivolved 
from  simj)ler  form.s.     But  it  does  not  necessarily  allirm 


126  THE  PHYSICAL  BASIS   OF  MIND. 

that  the  vast  variety  of  organisms  had  one  starting-point 
—  one  ancestor ;  on  tlie  contrary,  I  conceive  that  the 
principles  of  Evolution  are  adverse  to  such  a  view,  and 
insist  ratlier  on  the  necessity  of  innumerable  starting- 
points.     Let  us  consider  the  question. 

That  the  Theory  of  Descent  explains  many  of  the  facts 
must  be  admitted ;  but  there  are  many  which  it  leaves 
obscure ;  and  J\lr.  Darwin,  with  that  noble  calmness 
■which  distinguishes  him,  admits  the  numerous  difticulties. 
Whether  these  will  hereafter  be  cleared  away  by  an  im- 
provement in  the  Geological  Eecord,  now  confessedly 
imperfect,  or  by  more  exhaustive  exploration  of  distant 
countries,  none  can  say;  but,  to  my  mind,  the  probability 
is,  that  we  shall  have  to  seek  our  explanation  by  enlarg- 
ing the  idea  of  Natural  Selection,  subordinating  it  to  the 
laws  of  Organic  Affinity.  It  does  not  seem  to  me,  at  pres- 
ent, warrantable  to  assume  Descent  as  the  sole  principle 
of  morphological  uniformities ;  there  are  other  grounds 
of  resemblance  beyond  those  of  blood-relationship ;  and 
these  liave  been  too  much  overlooked ;  yet  a  brief  con- 
sideration will  disclose  that  similarity  in  the  physio- 
logical laws  and  the  conditions  of  Organic  Affinity  must 
produce  similarity  in  organisms,  independently  of  rela- 
tionship ;  just  as  similarity  in  the  laws  and  conditions 
of  inorganic  affinity  will  produce  identity  in  chemical 
species.  We  do  not  suppose  the  carbonates  and  phos- 
phates found  in  various  parts  of  the  globe,  or  the  families 
of  alkaloids  and  salts,  to  have  any  nearer  kinship  than 
that  which  consists  in  the  similarity  of  their  elements 
and  the  conditions  of  their  combination.  Hence,  in  or- 
ganisms, as  in  salts,  morphological  identity  may  be  due 
to  a  community  of  conditions,  rather  than  community  of 
descent.  Mr.  Darwin  justly  holds  it  to  be  "incredible 
that  individuals  identically  the  same  should  have  been 
produced  through  Natural  Selection  from  parents  s])ecijl- 


THE  NATURE   OF   LIFE.  127 

ccdly  distinct"  but  he,  since  he  admits  analogous  varia- 
tions, will  not  deny  that  identical  forms  might  issue  from 
parents  having  Mddely  different  origins,  provided  that 
these  parent  forms  and  the  conditions  of  their  reproduc- 
tion were  identical,  as  in  the  case  of  vegetable  and  animal 
resemblances.  To  deny  this  would  be  to  deny  the  law  of 
causation.  And  that  which  is  true  of  identical  forms 
under  identical  conditions  is  true  of  similar  forms  un- 
der similar  conditions.  When  History  and  Ethnology 
reveal  a  striking  uniformity  in  the  progression  of  social 
])hases,  we  do  not  thence  conclude  that  the  nations  are 
directly  related,  or  that  the  social  forms  have  a  common 
parentage ;  we  conclude  that  the  social  phases  are  alike 
because  they  have  had  common  causes.  A¥hen  chemists 
point  out  the  uniformity  of  type  which  exists  in  com- 
pounds so  diverse  in  many  of  their  properties  as  water 
and  sulphuretted  or  selenetted  hydrogen,  and  M'hen  they 
declare  phosphoretted  hydrogen  to  be  the  congener  of 
ammonia,  they  do  not  mean  that  the  one  is  descended 
from  the  other,  or  that  any  closer  link  connects  them 
than  that  of  resemblance  in  their  elements. 

In  the  case  of  vegetal  and  animal  organisms,  we  ob- 
serve such  a  community  of  elementary  sul)stance  as  of 
itself  to  imply  a  community  in  their  laws  of  combina- 
tion ;  and  under  similar  conditions  the  evolved  forms 
must  be  similar.  With  this  community  of  elementary 
substance,  there  are  also  diversities  of  substance  and  of 
co-operant  conditions ;  corresponding  witli  tliese  diversi- 
ties there  must  be  differences  of  form.  Thus,  although 
observation  reveals  that  the  bond  of  kiusliip  does  really 
unite  many  widely  divergent  forms,  and  tlie  princijilc  of 
Descent  with  Natural  Selection  will  account  for  many  of 
the  resemblances  and  differences,  there  is  at  present  no 
warrant  for  assuming  that  all  resemblances  and  differ- 
ences are  due  to  this  one  cause,  but,  on  the  contrary,  we 


128  THE  PHYSICAL  BASIS   OF  MIND. 

are  justified  iu  assuming  a  deeper  principle  which  may  be 
thus  formulated :  All  the  complex  organisms  are  evolved 
from  organisms  less  complex,  as  these  were  evolved  from 
simpler  forms ;  the  link  which  unites  all  organisms  is  not 
always  the  common  bond  of  heritage,  but  tlie  uniformity 
of  organized  substance  acting  under  similar  conditions. 

It  is  therefore  consistent  with  the  hypothesis  of  Evo- 
lution to  admit  a  variety  of  origins  or  starting-points, 
though  not  consistent  to  admit  the  sudden  appearance 
of  complex  Types,  sucli  as  is  implied  in  the  hypothesis 
of  specific  creations. 

119  a.  The  analogies  of  organic  forms  and  functions 
demand  a  more  exhaustive  scrutiny  than  has  yet  been 
given  them.  Why  is  it  that  vessels,  nerves,  and  bones 
ramify  like  branches,  and  why  do  these  branches  take  on 
the  aspect  of  many  crystalline  forms  ?  Why  is  it  that 
cavities  are  constantly  prolonged  in  ducts,  e.  g.  the  mouth 
succeeded  by  the  oesophagus,  the  stomach  by  the  intes- 
tines, the  bladder  by  the  urethra,  the  heart  by  the  aorta, 
the  ovary  by  the  oviduct,  and  so  on  ?  Wby  are  there 
never  more  than  four  limbs  attached  to  a  vertebral 
column,  and  these  always  attached  to  particular  verte- 
brae ?  Why  is  there  a  tendency  in  certain  tissues  to 
form  tubes,  and  in  these  tubes  commonly  to  assume  a 
muscular  coat  ?  *  To  some  of  these  queries  an  answer 
might  be  suggested  which  would  bring  them  under  known 
physical  laws.  I  merely  notice  them  here  for  the  sake 
of  emphasizing  the  fact  that  such  analogies  lie  deeply 
imbedded  in  the  laws  of  evolution,  and  tliat  what  has 
been  metaphorically  called  organic  crystallization  will 
account  for  many  similarities  in  form,  without  forcing  us 
to  have  recourse  to  kinship.  To  take  a  very  simple  case. 
No  one  will  maintain  that  the  crystalline  forms  of  snow 
have  any  kinship  with  the  plants  wliich  they  often  re- 

*  Even  in  the  nerve-sheaths  of  some  Annelids  there  are  muscles. 


THE   NATURE   OF   LIFE.  129 

semble.  Mr.  Spencer  has  noticed  tlie  development  of  a 
wing-bearing  brancli  from  a  wing  of  the  Ptilota  jjlamosa, 
when  its  nutrition  is  in  excess.  "  This  form,  so  strik- 
ingly like  that  of  the  feathery  crystallizations  of  many 
inorganic  substances,  proves  to  us  that  in  such  crystalli- 
zations the  simplicity  or  complexity  of  structure  at  any 
place  depends  on  the  quantity  of  matter  that  has  to  be 
polarized  at  that  place  in  a  given  time.  How  the  ele- 
ment of  time  modifies  the  result,  is  shown  by  the  famil- 
iar fact  that  crystals  rapidly  formed  are  small,  and  that 
they  become  larger  when  they  are  formed  more  slowly."  * 

It  may  be  objected,  and  justly,  that  in  the  resemblance 
between  crystals  and  organisms  the  analogy  is  purely 
that  of  form,  and  usually  confined  to  one  element,  where- 
as between  organisms  there  is  resemblance  of  substance 
no  less  than  of  form,  and  usually  the  organisms  are  alike 
in  several  respects.  The  answer  to  this  objection  is, 
that  wherever  there  is  a  similarity  in  the  causal  condi- 
tions (substance  and  history)  there  must  be  a  correspond- 
ing similarity  in  the  results ;  if  this  similarity  extends 
to  only  a  few  of  the  conditions,  the  analogy  will  be 
slight ;  if  to  several,  deep.  But  whetlier  slight  or  deep 
we  are  not  justified,  simply  on  the  ground  of  resemblance, 
in  assuming,  short  of  evidence,  that  because  they  are 
alike,  two  organisms  are  related  by  descent  from  a  com- 
mon ancestor. 

120.  Let  us  glance  at  a  few  illustrations.  It  has  been 
urged  as  a  serious  objection  to  Mr.  Darwin's  hypothesis,  f 
that  it^fails  to  explain  the  existence  of  phosphorescent 
organs  in  a  few  insects ;  and  certainly,  when  one  con- 
siders the  widely  different  orders  in  which  tliese  organs 
appear,  and  tlieir  absence  in  nearly  related  forms,  it  is 
a  difficulty.     In  noctilucae,  earthworms,  molluscs,  scolo- 

*  Spencrb,  Principles  of  JjiciJog!/,  II.  72. 
■y  Fai\'Ri:,  Variahilil.r.  de  I'Esp^cc,  p.  15. 

6*  I 


130  THE   niYSICAL   BASIS   OF   MIND. 

pendra,  and  fireflies,  we  may  easily  supi^ose  tlie  presence 
ot"  similar  organic  conditions  producing  tlie  luminosity; 
but  it  requires  a  strong  faith  to  assign  Descent  as  the 
cause.*  We  may  say  the  same  of  the  electric  organs 
possessed  by  seven  species  of  fish,  belonging  to  five 
widely  separated  genera.  Although  each  species  appears 
to  have  a  limited  geographical  range,  one  or  the  other  is 
found  in  almost  every  part  of  the  globe.  These  organs 
occupy  different  positions,  being  now  on  each  side  of  the 
head,  now  along  the  body,  and  now  along  the  tail ;  and 
in  different  species  they  are  innervated  from  different 
sources.  Their  intimate  structure  also  varies ;  as  appears 
from  the  remarkable  investigations  of  Max  Schultze.f 
They  cannot,  therefore,  be  homologous.  How  could  they 
have  arisen  ?  Xot  by  the  slow  accumulations  of  Natural 
Selection,  because,  until  the  organs  were  fully  formed, 
they  could  be  of  no  advantage  in  the  struggle ;  hence  the 
slow  growth  of  the  organ  must  have  proceeded  without 
the  aid  of  an  advantage  in  the  struggle  —  in  each  case 

*  These  luminous  organs  would  furnish  an  interesting  digression  if 
space  permitted  it.  The  student  is  referred  to  the  chapter  in  Milne 
Edwakds's  Leqons  sur  la  Physiolorjie  ct  V Anatomic  Comparee,  1863, 
VIII.  94,  sq.  Leydig,  Histologic,  1857,  p.  343.  Kolliker,  Microscopi- 
cal Journal,  18§8,  VIII.  166,  and  Max  Schultze,  Archiv  fur  viikros. 
Anat.,  1865,  p.  124.  My  friend  Schultze  vas  kind  enough  to  show 
me  some  of  his  preparations  of  the  organs  of  Lempyris  splciididula,  fiom 
which  the  drawings  in  his  memoir  were  made.  They  reminded  me  of 
the  electric  organs  in  fishes  by  a  certain  faint  analogy,  the  trachea  in 
the  one  holding  the  position  of  neiTCs  iu  the  other.  I  ma}"^  remark,  in 
passing,  that  it  is  not  every  phosphorescent  animal  that  has  distinct 
luminous  organs.  There  is  a  lizard  {Pterodactyl us  Gecko)  which  occa- 
sionally becomes  luminous.  "Asingiilar  circumstance  occurred  to  the 
colonial  surgeon,  who  related  it  to  me.  He  was  lying  awake  in  bed 
when  a  lizard  fell  from  the  ceiling  upon  the  top  of  his  mosquito-curtain  ; 
at  the  moment  of  touching  it  the  lizard  became  brilliantly  luminous, 
illuminating  the  objects  in  the  neighborhood,  much  to  the  astonishment 
of  the  doctor."     Collingwood,  Rambles  of  a  Naturalist,  1868,  p.  169. 

+  Max  Schultze,  Zur  Kenntniss  der  eledrischen  Organc  der  Fische, 
1858-9. 


THE   NATUEE   OF   LIFE.  131 

from  some  analogous  conditions  which  produced  a  dif- 
ferentiation in  certain  muscles.  The  fundamental  resem- 
blance to  muscles  was  pointed  out  by  Cams  long  ago. 
It  has  been  insisted  on  by  Leydig:*  and  Owen  says, 
"  The  row  of  compressed  cells  constituting  the  electric 
prism  of  the  Torpedo  offers  some  analogy  to  the  row  of 
microscopic  discs  of  which  the  elementary  muscle  fibre 
appears  to  consist."  f  We  must  not,  however,  forget 
that  tliese  resemblances  are  merely  such  as  suggest  that 
the  electric  organ  is  a  differentiation  of  the  substance 
which  elsewliere  becomes  muscular,  and  that  Dr.  Davy 
was  justified  in  denying  the  organ  to  be  muscular.  § 
That  it  is  substituted  for  muscle  cannot  be  doubted. 
Now,  although  we  are  entirely  ignorant  of  the  conditions 
which  cause  this  differentiation  of  substance  whicli  else- 
where becomes  muscular,  but  here  becomes  electric  organs, 
we  can  understand  that,  when  once  such  a  development 
had  taken  place,  if  it  in  any  way  profited  the  fish  in  its 
struggle  for  existence,  Natural  Selection  would  tend  to 
its  further  increase  and  propagation.  So  far  Mr.  Darwin 
carries  us  with  him ;  but  we  decline  proceeding  further. 
The  development  of  these  organs  in  fishes  so  widely  re- 
moved, does  not  imply  an  ancestral  community.  It  is 
interpretable  as  mere  growth  on  a  basis  once  laid ;  and 
therefore  would  occur  with  or  without  any  advantage  in 
the  struggle  with  rivals.  Tlie  similarity  in  concurrent 
conditions  is  quite  enough  to  account  for  the  resemblance 
in  structure.  This,  with  his  accustomed  candor,  Mr. 
Darwin  ailuiits.  "  If  the  electric  organs,"  he  says,  "  had 
been  inheiited  from  one  ancient  progenitor  thus  provided, 
we  might  have  expected  that  all  electric  fishes  would  be 
specially  rehited  to  each  other.     Nor  does  Geology  at  all 

♦  LeydiGj  Ilislolorjie,  1857,  p.  45. 

t  Owen,  Anatomy  of  the  Vertebrates,  1866,  I.  358. 

X  Davy,  llesearches,  Physiolo(jical  and  Anatomical,  139,  I.  33. 


132  THE  niYsiCAL  basis  of  mind. 

lead  to  the  belief  that  formerly  most  fishes  had  electric 
organs  wliich  most  of  their  modified  descendants  have 
lost." 

121.  It  may  seem  strange  that  he  should  nrge  a  diffi- 
culty against  his  hypothesis  when  it  could  be  avoided 
by  the  simple  admission  that  even  among  nearly  allied 
animals  great  differences  in  develoj)ment  are  observable, 
and  the  electric  organs  might  be  ranged  under  such 
diversities.  But  Mr.  Darwin  has  so  thorouohlv  wrought 
out  his  scheme,  that  he  foresees  most  objections,  and 
rightly  suspects  that  if  this  principle  of  divergent  devel- 
opment be  admitted,  it  will  cut  the  ground  from  under  a 
a  vast  array  of  facts  which  his  hypothesis  of  Descent 
requires. 

The  sudden  appearance  of  new  organs,  not  a  trace  of 
which  is  discernible  in  the  embryo  or  adult  form  of  organ- 
isms lower  in  the  scale,  —  for  instance,  the  phosphorescent 
and  electric  organs,  —  is  like  the  sudden  appearance  of 
new  instruments  in  the  social  organism,  such  as  the  print- 
ing-press and  the  railway,  wholly  inexplicable  on  the 
theory  of  Descent,*  but  is  explicable  on  the  theory  of 

*  "  If  it  could  be  demonstrated  that  any  complex  organ  existed  which 
could  not  possibly  have  been  fonned  by  numerous  successive  slight  modi- 
tications,  my  theory  would  absolutely  break  down." — Dakwix,  Origin 
of  Species,  5th  ed.  p.  227.  In  several  passages  insistence  is  made  on  this. 
"Natura  non  facit  saltum  "  may  be  perfectly  true  ;  but  without  impugn- 
ing the  Law  of  Continuity  we  may  urge  that  the  Law  of  Discontinuity 
is  equally  true.  The  one  is  an  abstract  ideal  conception  ;  the  other  is  a 
concrete  ideal  conception.  According  to  the  one,  eveiy  change  from  rest 
to  motion,  or  from  one  state  to  another,  must  pass  through  infinites  ;  ac- 
cording to  the  other  every  change  is  abrupt.  In  my  First  Series,  Vol.  I. 
p.  327,  I  have  shown  how,  on  mechanical  principles,  ever}'  change  in  an 
organism  must  be  abrupt.  A  glance  at  the  metamorphoses  of  the  em- 
bryo, or  the  stages  of  insect-development,  will  show  very  sudden  and 
abrupt  changes.  Let  me  also  cite  Mr.  Darwin  against  himself  :  "When 
we  remember  .such  cases  as  the  formation  of  the  more  complex  galls,  and 
certain  monstrcsities,  which  cannot  be  accounted  for  by  reversion,  cohe- 
.sion,  etc.,  and  sudden,  strmigly  marked  deviations  of  structure,  such  as 


THE   NATURE   OF   LIFE.  133 

Organic  Affinity.  For  observe :  if  we  admit  that  differ- 
entiations of  structure,  and  the  sudden  appearance  of 
organs,  can  have  arisen  spontaneously  —  i.  e.  not  heredi- 
tarily —  as  the  outcome  of  certain  changed  physical  con- 
ditions, we  can  hardly  refuse  to  extend  to  the  whole 
organism  what  we  admit  of  a  j)articular  organ.  If,  again, 
we  admit  that  organs  very  similar  in  structure  and  func- 
tion spontaneously  appear  in  organisms  of  widely  differ- 
ent kinds  —  e.  g.  the  phospliorescent  and  electric  organs 
—  we  must  also  admit  that  similar  resemblances  may  pre- 
sent themselves  in  organisms  having  a  widely  difCereut 
parentage ;  and  thus  the  admission  of  the  spontaneous 
evolution  of  closely  resembling  organs  carries  witli  it  the 
admission  of  the  spontaneous  evolution  of  closely  resem- 
bling organisms  :  that  the  protoplasm  of  muscular  tissue 
should,  under  certain  changed  conditions,  develop  into  the 
tissue  of  electric  organs,  is  but  one  case  of  the  law  that 
organized  substance  will  develop  into  organisms  closely 
resembling  each  other  when  the  conditions  have  been 
similar. 

122.  It  is  to  be  remarked  that  Mr.  Darwin  fi.xes  his 
attention  somewhat  too  exclusively  on  the  adaptations 
which  arise  during  the  external  struggle  for  existence,  and 
to  that  extent  neglects  the  laws  of  organic  alfinity ;  just 
as  Lamarck  too  exclusively  fixed  liis  attention  on  the 
influence  of  external  conditions  and  of  wants.  Not  that 
Mr.  Darwin  can  l)e  said  to  overlook  the  organic  laws ;  he 
simply  underestimates  the  part  tliey  play.  Occasionally 
he  seems  arrested  by  them,  as  when  instancing  the  "  trail- 
ing ])alm  in  the  JNIalay  Archipelago,  which  cliiul)S  the 
loftiest  trees  by  the  aid  of  exquisitely  constructed  hooks, 

the  appearance  of  a  moss-rose  on  a  cointnon  rcse,  we  must  admit  that  the 
organization  of  tlie  individual  is  cajjable  througli  if.s  own  laws  of  growth, 
inide.r  crrt.ain  cmulitions,  of  unchTgoing  great  modifications,  iiid(![)('ndent 
of  the  gradual  accumulation  of  sliglit  inherited  modifications."  —  Origin, 
ji.  151.     See  also  note  to  §  130,  further  on,  p.  142. 


134  THE  PHYSICAL  basis  of  mind. 

clustered  arouiul  the  ends  of  the  branches,  and  this  contriv- 
ance no  doubt  is  of  the  highest  service  to  the  plant ;  but 
as  there  are  nearly  similar  hooks  on  many  trees  which  are 
not  climbers,  the  hooks  on  the  palm  may  have  arisen  from 
unknown  laws  of  growth,  and  have  been  subsequently 
taken  advantage  of  by  the  plant  undergoing  furtlier  mod- 
ification and  becoming  a  climber." 

12r).  I  come  round  to  the  position  from  which  I  started, 
that  the  resemblances  traceable  among  animals  are  no 
proof  of  kinship ;  even  a  resemblance  so  close  as  to  defy 
discrimination  would  not,  in  itself,  be  such  a  proof.  The 
absolute  identity  of  chalk  in  Australia  and  in  Europe  is 
a  proof  that  tliere  was  absolute  identity  in  the  formative 
conditions  and  the  constituent  elements,  but  no  proof 
whatever  that  the  two  substances  were  originally  con- 
nected by  genesis.  In  like  manner  the  similarity  of  a 
plant  or  animal  in  Africa  and  Europe  may  be  due  to  a 
common  kinship,  but  it  may  also  be  due  to  a  common  his- 
tory. It  is  indeed  barely  conceivable  that  the  history, 
from  first  to  last,  would  ever  be  so  rigorously  identical  in 
two  parts  of  the  globe  as  to  produce  complex  identical 
forms  in  both ;  because  any  diversity,  either  in  structure 
or  external  conditions,  may  be  the  starting-point  of  a  wide 
diversity  in  subsequent  development ;  and  the  case  of 
organic  combinations  is  so  far  unlike  the  inorganic,  that 
while  only  one  form  is  possible  to  the  latter  (chalk  is 
either  formed  or  not  formed),  many  forms  are  possible 
to  organic  elements  owing  to  the  complexity  and  indefi- 
niteness  of  organic  composition.  But  although  forms  so 
allied  as  those  of  Species  are  not  readily  assignable  to  an 
identical  history  in  different  quarters  of  the  globe,  it  is 
not  only  conceivable,  but  is  eminently  probable,  that  Or- 
ders and  Classes  have  no  nearer  link  of  relationship  than 
is  implied  in  their  community  of  organized  substance  and 
their  common  history.     The  fact  that  there  is  not  a  single 


THE   NATUllE   OF  LIFE.  135 

mammal  common  to  Europe  and  Australia  is  explicable, 
as  Mr.  Darwin  explains  it,  on  the  ground  that  migration 
has  been  impossible  to  them ;  but  it  is  also  explicable  on 
tlie  laws  of  Evolution  —  to  have  had  mammals  of  the 
same  species  and  genera  would  imply  a  minute  coinci- 
dence in  their  history,  which  is  against  the  probabilities. 
Again,  in  the  Oceanic  Islands  there  are  no  Batrachians ; 
but  there  are  Reptiles,  and  these  conform  to  the  reptilian 
type.  ]\Ir.  Darwin  suggests  tliat  the  absence  of  Batrachia 
is  due  to  the  impossibility  of  migration,  their  ova  being 
destroyed  by  salt  water.  But  may  it  not  be  due  to  the 
divergence  from  the  reptilian  type,  which  was  effected 
elsewhere,  not  having  taken  place  in  these  regions  ? 
AVlien  we  find  the  metal  Tin  in  Prussia  and  Cornwall, 
and  nowhere  else  in  Europe,  must  we  not  conclude  that 
in  these  two  countries,  and  nowhere  else,  a  peculiar  con- 
junction of  conditions  caused  this  peculiar  evolution  ? 

124.  The  question  at  issue  is.  Are  the  resemblances 
observable  among  organic  forms  due  to  remote  kinship, 
and  tlieir  diversities  to  the  divergences  caused  by  adap- 
tation to  new  conditions  ?  or  are  the  resemblances  due 
to  similarities,  and  the  diversities  to  dissimilarities  in 
the  suhstance  and  history  of  organic  beings  ?  Are  we  to 
assume  one  starting-point  and  one  centre  of  creation,  or 
many  similar  starting-points  at  many  centres  ?  So  far 
from  believing  that  all  plants  and  animals  had  tlieir  origin 
in  one  primordial  cell,  at  one  yiarticular  spot,  from  which 
descendants  nn'grated  and  l)ecame  diversified  under  the 
diverse  conditions  of  tlieir  migration,  it  seems  to  me  more 
consistent  with  the  princijilc  of  Evolution  to  admit  a  vast 
variety  of  origins  more  or  less  resembling  each  other ; 
and  this  initial  resemblance  will  account  for  the  similari- 
ties still  traceable  under  the  various  forms  ;  while  the 
carbj  differences,  becoming  intensified  by  development  un- 
der different  conditions,  will  yield  the  diversities.     The 


136  THE   niYSICAL   BASIS   OF   MIND. 

evolution  of  organisms,  like  the  evolution  of  crystals,  or 
the  evolution  of  islands  and  continents,  is  determined, 
1st,  by  laws  inherent  in  the  substances  evolved,  and,  2d,  by 
relations  to  the  medium  in  which  the  evolution  takes 
place.  This  being  so,  we  may  a  priori  afiirm  that  the 
resultant  forms  will  have  a  community  strictly  correspond- 
ing with  the  resemblance  of  the  substances  and  their  con- 
ditions of  evolution,  together  with  a  diversity  correspond- 
ing with  their  differences  in  substance  and  conditions.  It 
is  usually  supposed  that  the  admission  of  separate  "  cen- 
tres of  creation  "  is  tantamount  to  an  admission  of  "  suc- 
cessive creations  "  as  interjn-eted  by  the  majority  of  those 
who  invoke  "  creative  fiats."  But  the  doctrine  of  Evolu- 
tion, which  regards  Life  as  making  its  appearance  conse- 
quent vpon  a  coneurrcnce  of  definite  conditions,  and  regards 
the  specific  forms  of  Life  as  the  necessary  consequences 
of  special  circumstances,  must  also  accept  the  probability 
of  similar  conditions  occurring  at  different  times  and  in 
different  places.  Upon  what  grounds,  cosmical  or  bio- 
logical, are  we  to  assume  that  on  only  one  microscopic 
spot  of  this  developing  planet  such  a  group  of  conditions 
was  found  —  on  only  one  spot  a  particle  of  protein  sub- 
stance was  formed  out  of  the  abundant  elements,  and 
under  conditions  which  caused  it  to  grow  and  multiply, 
till  in  time  its  descendants  overran  the  globe  ?-  The  hy- 
pothesis that  all  organic  forms  are  the  descendants  of  a 
single  germ,  or  of  even  a  few  germs,  and  are  therefore 
united  by  links  of  kinship  more  or  less  remote,  is  not 
more  acceptable  than  the  hypothesis  that  all  the  carbon- 
ates and  phosphates,  all  the  crystals,  and  all  tlie  strata 
found  in  different  parts  of  the  globe,  are  the  descendants 
of  a  single  nnolecadc,  or  a  few  molecules  ;  or,  —  since  this 
may  seem  too  extravagant,  —  than  that  the  various  mala- 
dies which  afflict  organic  beings  are,  in  a  literal  sense, 
members  of  fcimilu's  liaving  a  nearer  relationship  than 


THE   NATURE   OF   LIFE.  137 

that  of  being  the  jjhenomena  manifested  by  similar  organs 
under  similar  conditions  —  a  conception  wliicli  might  have 
been  accepted  by  those  metaphysical  pathologists  who 
regarded  Disease  as  an  entity.  Few  philosophers  have 
any  hesitation  in  supposing  that  other  planets  besides  our 
own  are  peopled  with  organic  forms,  though,  from  the 
"reat  differences  in  tlie  conditions,  tliese  forms  must  be 
extremely  unlike  those  of  our  own  planet.  If  separate 
worlds,  why  not  separate  centres  ?  The  conclusion  seems 
inevitable  that  wherever  and  whenever  the  state  of  things 
permitted  that  peculiar  combination  of  elements  known 
as  organized  substance,  there  and  then  a  centre  was  estab- 
lished —  Life  had  a  root.  From  roots  closely  resembling 
each  other  in  all  essential  characters,  but  all  more  or  less 
different,  there  have  been  developed  the  various  stems  of 
the  great  tree.  Myriads  of  roots  have  probably  perished 
witliout  issue ;  myriads  have  developed  into  forms  so  ill- 
adapted  to  sustain  the  fluctuations  of  the  medium,  so 
ill-fitted  for  the  struggle  of  existence,  that  they  became 
extinct  before  even  our  organic  record  begins ;  myriads 
have  become  extinct  since  then  ;  and  the  descendants  of 
those  which  now  survive  are  like  the  shattered  regiments 
and  companies  after  some  terrific  battle. 

125.  There  seems  to  me  only  one  alternative  logically 
permissible  to  the  Evolution  Hypotliesis,  namely,  that  all 
organic  forms  have  had  either  a  single  origin,  or  else 
numerous  origins  ;  in  otlier  word.s,  that  a  primordial  cell 
was  the  starting-point  from  which  all  organisms  liave 
been  successively  developed  ;  or  that  the  development 
issued  from  many  independent  starting-points,  more  or 
less  varied.  This  is  apparently  not  the  aspect  presented 
by  the  liypothesis  to  many  of  its  advocates ;  they  seem 
to  consider  that  if  all  organic  forms  arc  not  the  lineal 
descendants  of  one  progenitor,  they  must  at  any  rate  be 
the  descendants  of  not  more  than  four  or  five.     The  com- 


138  TIIK   niYSICAL   BASIS   OF   MIND. 

moil  belief  inclines  to  one.  Mr.  Darwin,  whose  caution 
is  as  leiiiai'kable  as  his  courage,  and  whose  candor  is 
delightful,  hesitates  as  to  which  conclusion  should  be 
adopted  :  "  I  cannot  doubt,"  he  sajs,  "  that  the  theory  of 
descent,  with  modifications,  embraces  all  the  members  of 
the  same  class.  I  believe  that  animals  have  descended 
from,  at  most,  only  four  or  five  progenitors,  and  plants 
from  an  equal  or  lesser  number.  Analogy  would  lead  me 
one  step  further,  namely,  to  the  belief  that  all  animals 
and  plants  have  descended  from  some  one  prototype. 
But  analogy  may  be  a'  deceitful  guide." 

126.  I  cannot  see  the  evidence  which  would  M-arrant 
the  belief  that  Life  originated  solely  in  one  microscopic 
lump  of  protoplasm  on  one  single  point  of  our  earth's 
surface  ;  on  the  contrary,  it  is  more  probable  that  from 
innumerable  and  separate  points  of  this  teeming  earth, 
myriads  of  protoplasts  sprang  into  existence,  ivlienever 
and  wherever  the  conditions  of  the  formation  of  organized 
substance  were  present.  It  is  probable  that  this  has  been 
incessantly  going  on,  and  that  every  day  new  protoplasts 
appear,  struggle  for  existence,  and  serve  as  food  for  more 
highly  organized  rivals  ;  but  whether  an  evolution  of  the 
lower  forms  is,  or  is  not,  still  going  on,  there  can  be  no 
reluctance  on  the  part  of  every  believer  in  Evolution  to 
admit  that  when  organized  substance  was  first  evolved,  it 
"was  evolved  at  many  points.  If  this  be  so,  the  commu- 
nity observable  in  organized  substance,  wherever  found, 
may  as  often  be  due  to  the  fact  of  a  common  elementary 
composition  as  to  the  fact  of  inheritance.  If  this  be  so, 
we  have  a  simple  explanation  both  of  the  fundamental 
resemblances  which  link  all  organisms  together,  and  of  the 
characteristic  diversities  which  separate  them  into  king- 
doms, classes,  and  orders.  The  resemblances  are  many, 
and  close,  because  the  forms  evolved  had  a  similar  ele- 
mentary composition,  and  their  stages  of  evolution  were 


THE    NATURE   OF   LIFE.  139 

determined  by  similar  conditions.  The  diversities  are 
many,  because  the  forms  evolved  had  from  the  first  some 
diversities  in  elementary  composition,  and  their  stages 
of  evolution  were  determined  under  conditions  which, 
though  similar  in  general,  have  varied  in  particulars. 
Indeed,  there  is  no  other  ground  for  the  resemblances 
and  differences  among  organic  beings  than  the  similari- 
ties and  dissimilarities  in  their  Substance  and  History ; 
and,  whether  the  similarities  are  due  to  blood-relation- 
ship, or  to  other  causes,  the  results  are  the  same.  There 
is  something  seductive  in  the  supposition  that  Life  radi- 
ated from  a  single  centre  in  ever-increasing  circles,  its 
forms  becoming  more  and  more  various  as  tliey  came 
under  more  various  conditions,  until  at  last  the  whole 
earth  was  crowded  with  diversified  existences.  "  From 
one  cell  to  myriads  of  complex  organisms,  through  count- 
less a^ons  of  development,"  is  a  formula  of  speculative 
grandeur,  but  I  cannot  bring  myself  to  accept  it ;  and  I 
think  that  a  lingering  influence  of  the  tradition  of  a  "  cre- 
ative fiat "  may  be  traced  in  its  conception.  May  we  not 
rather  assume  that  the  earth  at  the  dawn  of  Life  was  a 
vast  germinal  membrane,  every  slightly  diversified  point 
])roducing  its  own  vital  form ;  and  these  myriads  upon 
myriads  of  forms  —  all  alike  and  all  unlike  —  urged  by 
the  indwelling  tendencies  of  development,  struggled  with 
each  other  for  existence,  many  failing,  many  victorious, 
the  victors  carrying  their  tents  into  the  camping  ground 
of  the  vanquished  ?  The  point  raised  is  the  immense  im- 
])robability  of  organized  substance  having  been  evolved 
only  in  one  microscopic  spot ;  if  it  were  evolved  at  more 
than  one  spot,  and  under  slightly  varying  conditions, 
tlierc  would  necessarily  have  arisen  in  these  earliest  for- 
mations the  initial  diversities  which  afterwards  determined 
the  essential  independence  and  difference  of  organisms. 
129.  Let  us  for  a  moment  glance  at  the  resemblances  and 


140  THE  PHYSICAL  basis  of  mind. 

diversities  observable  in  all  organisms.  All  have  a  com- 
mon hasiii,  all  being  constructed  out  of  the  same  funda- 
mental elements :  carbon,  hydrogen,  nitrogen,  and  oxygen ; 
these  (the  organogens,  as  they  are  named),  with  var}^- 
ing  additions  of  some  other  elements,  make  up  what  we 
know  as  Organic  Substance,  vegetal  and  animal.  Another 
peculiarity  all  organisms  have  in  common,  namely,  that 
their  matter  is  neither  solid  nor  liquid,  but  viscid.  Be- 
side this  community  of  Substance  we  must  now  place  a 
community  of  History.  All  organisms  grow  and  mul- 
tiply by  the  same  process ;  all  pass  through  metamorphic 
stages  ending  in  death ;  all,  except  the  very  simplest, 
differentiate  parts  of  their  substance  for  special  uses,  and 
these  parts  (cilia,  membranes,  tubes,  glands,  muscles, 
nerves)  have  similar  characters  in  whatever  organism 
they  appear,  and  their  development  is  always  similar,  so 
that  the  muscles  or  nerves  of  an  intestinal  worm,  a  lob- 
ster, or  a  man,  are  in  structure  and  history  fundamentally 
alike.  When,  therefore,  we  see  that  there  is  no  biological 
character  of  fundamental  importance  which  is  not  uni- 
versal throughout  the  organic  world,  wlien  we  see  that  in 
Structure  and  History  all  organisms  have  a  community 
pervading  every  variety,  it  is  difficult  not  to  draw  the 
conclusion  that  some  hidden  link  connects  all  organisms 
into  one ;  and  wlien,  further,  it  is  seen  that  the  most 
divergent  forms  may  be  so  arranged  by  the  help  of  inter- 
mediate forms  only  slightly  varying  one  from  the  other, 
that  the  extreme  ends  —  the  monad  and  the  man  —  may 
be  connected,  and  a  genealogical  tree  constructed,  which 
will  group  all  forms  as  modified  descendants  from  a 
single  form,  the  hypothesis  that  kinship  is  the  hidden 
link  of  which  we  are  in  search  becomes  more  and  more 
cogent. 

130.    But  now  let  the  other  aspect  be  considered.     If 
there  is  an  unmistakable  uniformity,  there  is  also  a  diver- 


THE   NATURE   OF   LIFE.  141 

sity  no  less  unmistakable.  The  chemical  composition  of 
organic  substances  is  various.  Unlike  inorganic  sub- 
stances, the  composition  of  which  is  rigorously  definite, 
organic  substances  are,  within  narrow  limits,  variable  in 
composition  (§  45). 

I  pass  over  the  resemblances  and  differences  observed 
in  the  earliest  stages  of  development,  marked  as  they  are, 
and  direct  attention  to  the  fact,  that  down  at  what  must 
be  considered  the  very  lowest  organic  region,  we  meet 
with  differences  not  less  striking  than  those  met  with  in 
the  higliest,  we  find  structures  (if  structures  they  may  be 
calledj,  wliich  cannot  be  affiliated,  so  widely  divergent  is 
their  cuniposition.  The  structureless  vibrio,  for  example, 
is  not  only  capable  of  living  in  a  medium  destitute  of 
oxygen,  but  is,  according  to  M.  Pasteur,  actually  killed  by 
oxygen  ;  whereas  the  equally  simple  bacteria  can  no  more 
dispense  with  oxygen  than  other  animals  can.  Consider 
for  a  moment  the  differences  implied  in  the  fact  that  one 
organism  cannot  even  form  an  enveloping  membrane  to 
contain  its  protoplasm,  whereas  another  contrives  to  se- 
crete an  exquisite  shell ;  yet  between  the  naked  liliizopod 
and  the  shelled  Rhizopod  our  lenses  and  reagents  fail  to 
detect  a  difference.  One  Monad  can  assimilate  food  of 
only  one  kind,  another  Monad  assimilates  various  kinds.* 
What  a  revelation  of  chemical  differences  appears  in  the 
observations  of  M.  Pasteur  respecting  the  vibrio  and  bac- 
teria, in  a  fermentescible  liquid — the  former  beginning 
the  ])utrid  fermentation  which  the  latter  completes  !  We 
cannot  doubt  that  some  marked  difference  must  exist  be- 
tween the"  single-celled  organism  which  produces  alcoholic 
fermentation,  and  that  which  produces  acetic  fermenta- 
tion, and  that  again  which  produces  l)utyric  fermentation  ; 
and  if  we  find  distinctions  tlius  established  at  the  lowest 

*  On  till!  Nutrition  of  Monads,  seo  tlie  rtiinaikahle  memoir  by  CiEN- 
KOWSKi,  in  \\\ii  Archiv  fur  mikros.  ylnalomic,  I.  221,  sq. 


142  THE  niYsicAL  basis  of  mind. 

region  of  the  organic  series,  we  need  not  marvel  if  the 
ilistinctions  become  wider  and  more  numerous  as  the 
series  becomes  more  diversified.  The  structure  and  devel- 
opment of  an  organism  are  dependent  on  the  affinities  of 
its  constituent  molecules,  and  it  is  a  biological  principle 
of  great  importance  which  Sir  James  Paget  insists  on, 
wlien  he  shows  how  "  the  existence  of  certain  materials 
in  the  blood  may  determine  the  formation  of  structures  in 
which  they  may  be  incorporated."  *  Any  initial  diver- 
sity may  tlius  become  the  starting-point  of  a  considerable 
variation  in  subsequent  evolution.  *('  Thus,  supposing 
that  on  a  given  spot  there  are  a  dozen  protoplasts  closely 
resembling  eacli  other,  yet  each  in  some  one  detail  slightly 
varying  ;  if  tliis  variation  is  one  which,  by  its  relations  to 
the  external  medium,  admits  of  a  difference  in  the  assim- 
ilation of  materials  present  in  the  medium,  it  may  be  the 
origin  of  some  ncio  direction  in  development,  and  the  ulti- 
mate consequence  may  be  the  formation  of  a  shell,  an 
internal  skeleton,  a  muscle,  or  a  nerve.     Were  this  not  so, 

*  Paget,  Lectures  on  Surgical  Pathologij,  edited  hy  Turner,  1865, 
p.  19. 

t  It  has  recently  been  sliown  that  certain  Crustacea  vary  not  only  from 
species  to  species,  but  from  genus  to  genus,  when  living  in  water  of  different 
degrees  of  saltness.  By  continued  dilution  of  the  salt  water  an  Artcmia 
was  developed  into  another  .species,  and  this  again  into  a  Brmichijixs  — 
a  genus  of  large  dimensions,  with  an  extra  abdominal  segment,  and  a 
different  tail  ;  a  genus,  moreover,  Mhich  is  propagated  sexually,  whereas 
the  Artcmia  is  parthenogenetic,  as  a  rule.  See  Nature,  1876,  June  8, 
p.  133. 

The  exceeding  importance  of  this  fact  is,  that  it  proves  sjjpcific  and 
even  generic  differences  to  originate  simply  through  the  gradual  changes 
of  the  medium  and  the  adaptation  of  the  organism  to  these  new  condi- 
tions. It  also  disproves  the  very  common  notion  —  adopted  even  by  Mr. 
Darwin  himself —  that  "  organic  beings  must  be  exposed  during  several 
generations  to  new  conditions  to  cause  any  appreciable  amount  of  varia- 
tion." Again,  "Natural  Selection,  if  it  be  a  true  principle,  will  banish 
the  belief  of  any  groat  and  .sudden  modification  of  structure."  —  Comp. 
note  to  §  121,  p.  132. 


THE   NATURE   OF   LIFE,  *       143 

it  would  be  impossible  to  explain  such  facts  as  that  chit- 
ine  is  peculiar  to  the  Articulata,  cellulose  to  Molluscoida, 
carbonates  of  lime  to  Mollusca  and  Crustacea,  and  phos- 
phates to  Vertebrata  —  all  assimilated  from  the  same 
external  medium.  But  we  see  that  from  this  medium 
one  organism  selects  the  materials  which  another  rejects  ; 
and  this  selection  is  determined  by  the  nature  of  the 
structure:  which  assimilates  only  those  materials  it  is 
fitted  to  assimilate.  We  hear  a  great  deal  of  Adaptation 
determining  changes  of  structure  and  function,  and  are 
too  apt  to  regard  this  process  as  if  it  were  not  intimately 
dependent  on  a  corresponding  structural  change.  By  no 
amount  of  external  influence  which  left  the  elementary 
composition  of  the  structure  unchanged,  could  an  organ- 
ism with  only  two  tissues  be  developed  into  an  organism 
with  three  or  four.  By  no  supply  or  stimulus,  could  an 
animal  incapable  of  assimilating  peroxide  of  iron  acquire 
red  blood  corpuscles,  although  it  miglit  have  the  iron 
without  the  corpuscles  ;  nor  could  an  oyster  form  its  shell 
unless  capable  of  assimilating  carbonate  of  lime.  For 
myriads  of  years,  in  seas  and  ponds,  nnder  endless  varie- 
ties of  external  conditions,  the  amcebte  have  lived  and 
died  without  forming  a  solid  envelope,  althougli  the  ma- 
terials were  abundant,  and  other  organisms  equally  sim- 
ple have  formed  envelopes  of  infinite  variety.  In  all  the 
seas,  and  from  the  earliest  ages,  zoophytes  have  lived,  and 
assumed  a  marvellous  variety  of  shapes  and  specialization 
of  functions  ;  but  although  some  of  them  have  acquired 
muscles,  none  liave  acquired  true  nerves,  none  bone. 
Ages  upon  ages  rolled  on  before  fishes  were  capabhi  of 
forming  bone  ;  and  thousands  are  still  incapable  of  form- 
ing it,  though  living  in  the  same  waters  as  the  osseous 
fishes. 

131.    "  Ivooking  to  the  dawn  of  life,"  says  IMr.  Darwin 
(repeating  an   objection   urged   against   his  hypothesis), 


144      •  THE   PHYSICAL   BASIS   OF   MIND. 

"  when  all  organic  beings,  as  we  imagine,  presented  the 
simplest  structure,  how  could  the  first  steps  in  advance- 
ment, or  in  the  differentiation  and  specialization  of  parts 
have  arisen  ?  I  can  make  no  sufficient  answer  ;  and  can 
only  say  that,  as  we  have  no  facts  to  guide  us,  all  specu- 
lation would  be  baseless  and  useless." 

Where  Mr.  Darwin  hesitates,  lesser  men  need  extra 
caution ;  but  I  must  risk  the  danger  of  presumption,  at 
least  so  far  as  to  suggest  that  while  an  answer  to  this 
question  is  difiicult  on  that  dynamical  view  of  Evolution 
which  regards  Function  as  determining  Structure,  it  is 
less  difficult  on  the  statico-dynamical  view  propounded  in 
these  pages  ;  the  difficulty  which  besets  the  explanation 
when  all  the  manifold  varieties  of  organic  forms  are  con- 
ceived as  the  successive  divergences  from  an  original 
starting-point,  is  lessened  when  a  variety  of  different 
starting-points  is  assumed,  in  each  of  which  some  initial 
diversity  prepared  the  way  for  subsequent  differentia- 
tions ;  just  as  we  know  that  between  the  ovum  of  a  ver- 
tebrate and  the  ovum  of  an  invertebrate,  similar  as  they 
are,  there  is  a  diversity  which  manifests  itself  in  their 
subsequent  evolution.  If  Function  is  determined  by 
Structure,  and  Evolution  is  the  product  of  the  two,  it  is 
clear  that  the  different  directions  in  the  lines  of  develop- 
ment will  have  their  origin  in  structural  differences,  and 
not  in  the  action  of  external  circumstances,  unless  these 
previously  bring  about  a  structural  change.  The  action 
of  the  medium  on  the  organism  is  assuredly  a  potent  fac- 
tor which  Biology  cannot  ignore  :  but  the  organism  itself 
is  a  factor,  and  according  to  its  nature  the  influence  of 
the  medium  is  defined.     (§  118.) 

132.  Quitting  for  a  moment  the  track  of  this  argu- 
ment, let  us  glance  at  the  resemblances  and  differences 
observable  in  Plants  and  Animals,  because  most  people 
admit  that  these  have  separate  origins.     The  resemblan- 


THE   NATURE   OF   LIFE.  145 

ces  are  scarcely  less  significant  than  those  existing  among 
animals.  Both  have  a  similar  basis  of  elementary  com- 
position ;  not  only  are  both  formed  out  of  protoplasts 
with  similar  properties,  but  in  both  the  first  step  from  the 
protoplasm  to  definite  structure  is  the  Cell.  And  the  life 
of  this  Cell  is  remarkably  alike  in  both,  its  phases  of  de- 
velopment being  in  many  respects  identical;  nay,  even 
such  variations  as  obtain  in  the  cell-membranes  are  curi- 
ously linked  together  by  a  community  in  the  formative 
process.*  In  both  Plants  and  Animals  we  find  individ- 
uals constituted  —  1st,  by  single  cells  ;  2d,  by  groups 
of  cells  undistinguishable  among  each  other ;  and  3d,  by 
groups  of  differentiated  cells.  In  both  we  find  colonies  of 
individuals  leading  a  common  life.  In  both  the  processes 
of  Nutrition  and  Eeproduction  are  essentially  similar; 
both  propagate  sexually  and  asexually ;  both  exhibit  the 
surprising  phenomena  of  parthenogenesis  and  alternate 
generations.  In  both  there  are  examples  of  a  free-roving 
embryo  which  in  maturity  becomes  fixed  to  one  spot,  los- 
ing its  locomotive  organs  and  developing  its  reproductive 
organs.  In  both  the  development  of  the  reproductive 
organs  is  the  climax  wlucli  carries  Death.  So  close  is  the 
analogy  between  plant-lil'e  and  animal-life,  that  it  even 
reaches  the  properties  usually  held  to  be  exclusively  ani- 
mal ;  I  mean  that  even  sliould  we  hesitate  to  accept  Cohn's 
discovery  of  the  muscles  in  certain  plants,!  ^^'<2  cannot  deny 

*  C^onipare  Leydig,  Vom  Bau  des  Ihierischcn  Kurprrs,  1864,  ji.  27. 

t  Fekdinand  Cohn,  Die  contractile  Gcwcle  im  Pjlanzenreich,  1862. 
I>y  a  scries  of  numerous  well-devised  experiments,  Colin  found  tliat  in 
the  stamen  of  the  centauria  a  tissue  exists  which  is  excitahh;  by  the  same 
stimula  as  muscle  is,  and  which  reacts  like  muscle,  descrii)ing  a  similar 
( urve  when  excited,  and,  after  reaching  its  maximum,  relaxing.  Like 
the  nmscle  it  becomes  fatigued  by  repeated  contraction,  and  recovers  its 
) lowers  by  repo.se.  Like  the  muscle  it  may  be  rendered  tetanic.  (The 
researches  of  Dr.  Buudon  Sandeiison  and  Mr.  Dai:win  have  .since  placed 
beyond  a  doubt  the  Contractility  and  Sensibility  of  certain  plants.) 

VtiL.    III.  7  J 


14G  THE  niYsiCAL  basis  of  mind. 

that  plants  exhibit  Contractility  ;  and  should  we  refuse  to 
interpret  as  Sensibility  the  phenomena  exhibited  by  the 
Sensitive  Plants,  we  cannot  deny  that  they  present  a  very 
striking  analogy  to  the  phenomena  of  Sensibility  exhib- 
ited by  animals. 

133.  It  is  unnecessary  to  continue  this  enumeration, 
which  might  easily  be  carried  into  minute  detail.  A 
chapter  of  such  resemblances  would  only  burden  the 
reader's  mind,  without  adding  force  to  the  conclusion 
that  a  surprising  community  in  Substance  and  Life- 
history  must  be  admitted  between  Plants  and  Animals. 
This  granted,  we  turn  to  the  differences,  and  find  them 
no  less  fundamental  and  detailed.  Chemistry  tells  us 
nothing  of  the  differences  in  the  protoplasms  from  which 
animals  and  plants  arise ;  but  that  initial  differences 
must  exist  is  proved  by  the  divergence  of  the  products. 
The  vegetable  cell  is  not  the  animal  cell ;  and  although 
both  plants  and  animals  have  albumen,  fibrine,  and  case- 
ine,  the  derivatives  of  these  are  unlike.  Horny  substance, 
connective  tissue,  nerve  tissue,  chitine,  biliverdine,  crea- 
tine, urea,  hippuric  acid,  and  a  variety  of  other  products 
of  evolution  or  of  waste,  never  appear  in  plants ;  while 
the  hydrocarbons  so  abundant  in  plants  are,  with  two  or 
three  exceptions,  absent  from  animals.  Such  facts  imply 
differences  in  elementary  composition ;  and  this  result  is 
further  enforced  by  the  fact  that  where  the  two  seem  to 
resemble,  they  are  still  different:  the  plant  protoplasm 
forms  various  cells,  but  never  forms  a  cartilage-cell  or 
nerve-cell ;  fibres,  but  never  a  fibre  of  elastic  tissue ; 
tubes,  but  never  a  nerve  tube ;  vessels,  but  never  a  vessel 
with  muscular  coatings ;  solid  "  skeletons,"  but  always 
from  an  organic  substance  {cellulose),  not  from  phosphates 
and  carbonates.  In  no  one  character  can  we  say  that 
the  plant  and  the  animal  are  identical;  we  can  only 
point  throughout  the  two  kingdoms  to  a  great  similarity 
accompanying  a  radical  diversity. 


THE   NATURE   OF   LIFE.  147 

t 

134.  Having  brought  together  the  manifold  resem- 
blances, and  the  no  less  marked  diversities,  we  must  ask 
what  is  their  significance  ?  Do  the  resemblances  imply 
a  community  of  origin,  an  universal  kinship  ?  If  so,  the 
diversities  will  be  nothing  more  than  the  divergences 
which  have  been  produced  by  variations  in  the  Life- 
history  of  the  several  groups.  Or  —  taking  the  alterna- 
tive view  —  do  the  diversities  imply  radical  differences 
of  origin  ?  If  so,  the  resemblances  will  be  nothing  more 
than  the  inevitable  analogies  resulting  from  Organized 
Substance  being  everywhere  somewhat  similar  in  compo- 
sition, and  similar  in  certain  phases  of  evolution.  To 
state  the  former  position  in  the  simplest  way,  we  may 
assume  that  of  two  masses  of  protoplasm  having  a  com- 
mon parentage,  one,  by  the  accident  of  assimilating  a 
certain  element  not  brought  within  the  range  of  the 
other,  thereby  becomes  so  differentiated  as  to  form  the 
starting-point  of  a  series  of  evolntions  widely  divergent 
from  those  possible  to  its  congener ;  and  at  each  stage  of 
evolution  tlie  introduction  of  a  new  element  (made  possi- 
ble by  that  stage)  will  form  the  origin  of  a  new  variation. 
It  is  thus  feasible  to  reduce  all  organic  forms  to  a  pri- 
mordial protoplasm,  in  the  evolutions  of  which  successive 
differentiations  have  been  established.  On  the  other  hand, 
it  is  equally  feasible  to  assume  that  the  existence  of 
radical  differences  must  be  invoked  to  account  for  the 
possibility  of  the  successive  differentiations. 

135.  The  hunt  after  resemblances  has  led  to  nnu^li 
mistaken  speculation ;  and  with  reference  to  the  to])ic 
now  before  us,  it  may  be  urged,  that  although  by  attacli- 
ing  ourselves  to  the  points  of  community,  in  disregard  of 
the  diversities,  we  may  make  it  appear  that  all  animals 
have  a  common  parentage,  and  that  plants  and  animals 
are  merely  divergent  groups  of  tlie  same  prototype,  a 
rigorous  logic  will  force  us  onwards,  and  compel  us  to 


148  THE  PHYSICAL  basis  of  mind. 

admit  tliat  a  kinship  no  less  real  unites  the  organic  with 
the  inorganic  world.  Tor  upon  what  principle  are  we  to 
pause  at  the  cell  or  protoplasm  ?  If  by  a  successive 
elimination  of  differences  we  reduce  all  organisms  to  the 
cell,  we  must  go  on  and  reduce  the  cell  itself  to  the 
chemical  elements  out  of  which  it  is  constructed ;  and  in- 
asmuch as  these  elements  are  all  common  to  the  inorganic 
world,  the  only  difference  being  one  of  synthesis,  w'e 
reach  a  result  which  is  the  stultification  of  all  classification, 
namely,  the  assertion  of  a  kinship  which  is  unixersal. 
We  must  bear  in  mind  that  all  things  may  be  reduced 
to  a  common  root  by  simply  disregarding  their  differences. 
All  things  are  alike  when  we  set  aside  their  unlikeness. 

136.  Suppose,  for  the  sake  of  illustration,  we  regard 
an  Orchestra  in  the  light  of  the  Development  Hypothesis. 
The  various  instruments  of  which  it  is  composed  have 
general  resemblances  and  particular  differences,  not  unlike 
those  observable  in  various  organisms  ;  and  as  Ave  proceed 
in  the  work  of  classification  we  quickly  discover  that 
they  may  be  arranged  in  groups  analogous  to  the  Sub- 
kingdoms,  Classes,  Orders,  Genera,  and  Species  of  the 
organic  world.  Each  group  has  its  cardinal  distinction, 
its  initial  point  of  divergence.  All  musical  instruments 
resemble  each  other  in  the  fundamental  character  of  pro- 
ducing Tone  by  the  vibrations  of  their  substance.  Tliis 
may  be  called  their  organic  basis.  The  first  marked 
difference  which  determines  the  character  of  two  sub- 
kingdoms  (namely,  instruments  of  Percussion  and  Wind 
instruments)  arises  from  a  difference  in  the  method  of  im- 
pressing the  vibrations ;  and  the  grand  divisions  of  these 
sub-kingdoms  arise  from  the  nature  of  the  vibrating  sub- 
stances. Each  type  admits  of  many  modifications,  but 
the  primary  distinction  is  ineffaceable.  We  can  conceive 
the  Pipe  modified  into  a  Flute,  a  Flageolet,  a  Clarionet, 
a   Hautbois,  a  Bassoon,  or   a  Fife,  by  simple   accessory 


THE   NATUEE   OF   LIFE.  149 

changes ;  to  modify  the  Pipe  into  a  Trumpet,  and  thus 
produce  the  peculiar  timhre  of  the  trumpet,  would  be 
impossible  except  by  the  substitution  of  a  new  material ; 
by  replacing  the  wood  with  metal  we  may  adhere  to  the 
old  Type,  but  we  have  created  a  new  Class.  (Attention 
is  requested  to  this  point,  because  the  current  views 
respecting  the  transmutation  of  tissues,  which  seem  to 
lend  a  decisive  support  to  the  hypothesis  of  the  trans- 
mutation of  species  are  very  commonly  vitiated  by  the 
confusion  of  transformation  with  substitution.  No  ana- 
tomical element  is  transformed  into  another  specifically 
different  —  an  epithelial-cell  into  a  nerve-cell,  for  instance 
—  but  one  anatomical  element  is  frequently  suhstituted 
for  another.)  To  convert  the  Pipe  or  the  Trumpet  into 
a  Violin  or  a  Drum  would  be  impossible.  We  can  follow 
the  modifications  of  a  Tambourine  into  a  Drum  or  Ket- 
tle-drum, but  no  modifications  of  these  will  yield  the 
Cymbals.  That  is  to  say,  the  vibrating  materials  — 
wood,  metal,  parchment,  and  the  combination  of  wood 
and  strings  —  have  peculiar  properties,  and  the  instru- 
ments formed  of  such  materials  must  necessarily  from 
the  very  first  belong  to  different  groups,  each  subdivision 
of  the  groups  being  dependent  on  some  characteristic 
difference  in  methods  of  impressing  the  vibrations,  or  in 
the  materials.  Although  all  musical  instruments  have 
a  common  property  and  a  common  purpose,  we  do  not 
regard  them  as  transformations  of  one  primitive  instru- 
ment ;  their  kindred  nature  is  a  subjective  conception ; 
the  analogies  are  numerous  and  close,  but  we  know  their 
origin.  It  is  obvious  that  men  being  pleased  by  musical 
tones,  have  been  led  by  their  deliglit  to  construct  instru- 
ments whenever  they  have  discovered  substances  capable 
of  musical  vibrations,  or  methods  of  impressing  sucli 
vibrations.  By  substituting  the  bow  for  the  plectrum  or 
the  fingers,  they  may  have  changed  the  Lyre  into  the 


150  THE   niYSICAL  BASIS   OF   MIND. 

Violin,  Viola,  Violoncello,  and  Bass.  (It  seems  histori- 
cally probable  that  the  real  origin  of  the  Violin  class  was 
an  instrument  with  one  string  played  on  by  a  bow.)  ]>y 
grouping  together  Pipes  of  various  sizes  they  got  the  Pan- 
pipes ;  by  substituting  metal  and  enlarging  the  blowing 
apparatus  they  got  the  Organ.  By  beating  on  stretched 
parchment  wdth  the  finger,  they  got  the  Tambourine  and 
Tom-Tom ;  by  doubling  this  and  using  a  stick  they  got 
the  Drum.  By  beating  metal  with  metal  they  got  the 
Cymbals  ;  by  beating  wood  they  got  the  Castanets. 

137.  The  application  of  this  illustration  is  plain.  Just 
as  a  wind-instrument  is  incapable  of  becoming  a  stringed 
instrument,  so  a  Mollusc,  with  all  its  muscles  unstriped, 
and  its  nervous  system  unsymmetrical,  is  incapable  of 
becoming  a  Crustacean,  with  all  its  muscles  striped  and 
its  nervous  system  symmetrical.  Indeed  there  are  proba- 
bly few  biologists  of  the  present  day  who  imagine  the 
transmutation  of  one  kind  into  the  other  to  be  possible  ; 
but  many  biologists  assume  that  both  may  have  been 
evolved  from  a  common  root.  The  point  is  beyond  proof; 
yet  I  think  there  is  a  greater  probability  in  the  assump- 
tion that  both  were  evolved  from  different  roots.  At  any 
rate,  one  thing  is  certain ;  a  divergence  could  only  have 
been  effected  by  a  series  of  siibstitutions ;  and  the  question 
when  and  how  these  substitutions  took  place  is  unan- 
swerable :  one  school  believes  them  to  have  been  creative 
fiats,  the  other  school  believes  them  to  have  been  trans- 
mutations. 

138.  When  we  see  an  annelid  and  a  vertebrate  resem- 
bling each  other  in  some  special  point  which  is  not  com- 
mon either  to  their  classes  or  to  any  intermediate  classes  — 
as  when  we  see  the  wood-louse  (Oniscus)  and  the  hedgehog- 
defend  themselves  in  the  same  strange  way  by  rolling  up 
into  a  ball  —  we  caimot  interpret  this  as  a  trace  of  distant 
kinship.     When  we  see  a  breed  of  pigeons  and  a  breed 


THE   NATURE   OF   LIFE.  151 

of  canaries  turning  somersaults,  and  one  of  the  Bear  fam- 
ily (Iiatd)  given  to  the  same  singular  habit,  we  can  hardly 
suppose  that  this  is  in  each  case  inherited  from  a  common 
progenitor.  When  we  see  one  savage  race  tipping  arrows 
with  iron,  and  another,  ignorant  of  iron,  using  poison, 
there  is  a  community  of  object  effected  by  diversity  of 
means ;  but  the  analogy  does  not  necessarily  imply  any 
closer  connection  between  the  two  races  than  the  fact  that 
men  with  similar  faculties  and  similar  wants  find  out  sim- 
ilar methods  of  supplying  their  wants.  Even  those  who 
admit  that  the  human  race  is  one  family,  and  that  the 
A'arious  peoples  carried  with  them  a  common  fund  of 
knowledge  wdien  they  separated  from  the  parent  stock, 
may  still  point  to  a  variety  of  new  inventions  and  new 
social  developments  which  occurred  quite  independently 
of  each  other,  yet  are  strikingly  alike.  Their  resemblance 
will  be  due  to  resemblance  in  the  conditions.  The  exist- 
ence, for  example,  of  a  religious  worship,  or  a  social  insti- 
tution, in  two  nations  widely  separated  both  in  time  and 
space,  and  under  great  historical  diversities,  is  no  absolute 
])roof  that  these  two  nations  are  from  the  same  stock,  and 
that  tlie  ideas  have  the  same  parentage.  It  may  be  so; 
it  may  be  otherwise.  It  may  be  an  analogy  no  more  im- 
plying kinship  than  the  fact  of  ants  making  slaves  of 
other  ants  (and  these  the  black  ants !)  implies  a  kinship 
with  men.  Given  an  organization  wliich  in  tlie  two  na- 
tions is  alike,  and  a  history  which  is  in  certain  character- 
istics analogous,  there  must  inevitably  result  religious  and 
social  institutions  liaving  a  corresponding  resemblance. 
I  do  not  wisli  to  imply  that  the  researches  of  philologists 
and  ethnologists  are  misdirected,  or  that  their  conclusions 
respecting  the  kinship  of  mankind  are  to  be  rejected  ;  I 
only  urge  the  consideration  that  perhaps  too  mucli  stress 
is  laid  on  community  of  l)lood,  and  not  enough  on  com- 
munity of  conditions. 


152  THE  PHYSICAL   BASIS   OF  MIND. 

RECAPITULATION. 

139.  The  various  lines  of  argument  may  here  be  reca- 
pitulated. The  organic  world  presents  a  spectacle  of  end- 
less diversity,  accompanied  by  a  pervading  uniformity. 
The  general  resemblances  in  forms  and  functions  are  more 
or  less  masked  by  particular  differences.  The  resem- 
blances, it  is  said,  may  be  all  due  to  kinship,  all  the  living- 
individuals  having  descended  from  a  primordial  cell ;  and 
at  each  stage  of  the  descent  the  adaptations  to  new  con- 
ditions may  have  issued  in  deviations  from  the  ancestral 
form,  while  the  process  of  Natural  Selection  giving  sta- 
bility to  those  variations  which  best  fitted  the  organism 
in  the  struggle  of  existence,  has  made  greater  and  greater 
gaps,  and  produced  more  marked  diversities  among  the 
descendants.  This  is  the  Darwinian  Theory :  "  On  my 
theory  unity  of  Type  is  explained  by  unity  of  Descent." 

140.  By  the  general  consent  of  biologists,  this  theory 
is  held  to  explain  many  if  not  all  the  observed  facts.  It 
is  a  very  luminous  suggestion  ;  but  it  requires  an  enlarge- 
ment so  as  to  include  Organic  Affinity ;  and  when  once 
this  fundamental  principle  is  admitted,  it  brings  with  it 
very  serious  doubts  as  to  the  theory  of  Descent.  We  are 
then  entitled  to  assume  that  many  of  the  most  striking 
resemblances,  instead  of  being  due  to  kinship,  are  due 
simply  to  the  general  principle  that  similar  causes  must 
have  similar  effects,  and  that  organic  substances  having  a 
very  close  resemblance,  organized  substances  must  have 
similar  stages  of  evolution  imder  similar  conditions  ;  and 
thus  organs  will  necessarily  take  on  very  similar  forms  in 
very  different  organisms  (for  example,  the  eye  of  the 
cephalopod  and  the  eye  of  the  vertebrate),  and  organisms 
having  widely  different  parentage  may  closely  resemble 
each  other.  If  we  are  entitled  to  assume  that  protoplasm 
appeared  not  in  one  microscopic  spot  alone,  but  in  many 


THE  NATURE   OF  LIFE.  153 

places  and  in  vast  quantities  —  and  this  is  surely  the 
more  justifiable  assumption  —  then  we  must  also  admit 
that  these  germinal  starting-points  were  from  the  first,  or 
very  shortly  afterwards,  differentiated  by  variations  in 
their  elementaiy  composition.  Now  we  know  that  a  very 
minute  change  in  composition  may  lead  to  immense  dif-' 
ferences  in  evolution.  Thus  the  descendants  of  two 
slightly  different  progenitors  may,  by  continual  differen- 
tiation, become  very  markedly  unlike  ;  yet,  because  of  the 
original  resemblance  of  their  substances,  they  will  reveal 
a  pervading  similarity. 

While  it  is  thus  conceivable  that  all  organisms  may 
resemble  each  other,  and  all  differ,  owing  to  the  similari- 
ties and  diversities  in  the  "  conditions  of  existence  "  (and 
among  those  conditions  that  of  descent  is  of  wide  range), 
it  is  not  very  readily  conceivable  how  advantage  in  the 
external  struggle  could  have  determined  the  varieties  of 
form  and  function,  because  many  differentiations  give  no 
superiority  in  the  struggle.  As  Mr.  St.  George  Mivart 
urges,  "  Natural  Selection  utterly  fails  to  account  for  the 
conservation  and  development  of  the  minute  and  rudi- 
mentary beginnings,  the  slight  and  infinitesimal  com- 
mencements of  structures,  however  useful  those  structures 
may  afterwards  become."*  And  this  is  undeniable  on  the 
supposition  that  Natural  Selection  is  an  agency  not  iden- 
tical with  the  variations  of  growth,  but  exclusively  con- 
fined to  the  accumulation  of  favorable  variations. 

141.  In  estimating  the  two  hypotheses  —  First,  of 
Descent  from  one  primordial  germ,  and  the  niodifications 
due  to  Natural  Selection,  or,  as  I  should  say,  expressed  in 
Selection ;  and  Secondly,  of  Descent  from  innumerable 
germs  having  initial  differences,  whicli  differences  radiated 
into  the  marked  modifications,  there  is  this  superiority  to 
be  claimed  for  the  first,  that  it  is  more  easily  handled  as 

*  MiVAKT,  The  Genesis  of  Species,  1871,  p.  23. 

7* 


154  THE  niYsiCAL  basis  of  mind. 

an  aid  to  research,  and  is  therefore  more  decidedly  useful. 
The  laws  of  Organic  Affinity  are  at  present  too  obscure 
for  any  successful  application.  I  only  wish  to  point  out 
that  the  theory  of  Descent  is  an  imaginary  construction 
of  what  may  have  been  the  process  of  species-formation, 
not  a  transcription  of  the  process  observed.  It  constructs 
an  imaginary  Type  as  progenitor  of  a  long  line  of  widely 
different  descendants.  The  annelid  which  is  taken  as  the 
ancestor  of  the  vertebrates  is  not  any  annelid  known 
either  to  zoologists  or  geologists,  but  a  generalized  and 
imaginary  type.  So  daringly  liberal  is  the  imagination 
in  endowing  the  ancestor  with  whatever  may  be  required 
for  the  descendants,  that  Mr.  Darwin  thinks  it  probable, 
from  what  we  know  of  the  embryos  of  vertebrates,  that 
these  animals  "  are  the  modified  descendants  of  some  an- 
cient progenitor  which  was  furnished  in  its  adult  state 
with  branchiae,  a  swim-bladder,  four  simple  limbs,  and  a 
long  tail,  all  fitted  for  an  organic  life,"  (p.  533) ;  and  Dr. 
Dohrn  conceives  the  original  type  to  have  contained 
within  itself  all  that  has  been  subsequently  evolved  in 
the  highest  vertebrate,  the  other  and  less  elaborate  organ- 
isms being  mere  degradations  from  this  type.*  This  use 
of  the  imagination,  although  not  without  advantages,  is 
also  not  without  dangers.  It  may  direct  research,  it  must 
not  be  suffered  to  replace  research. 

*  DoHRX,  Der  Urs2}rung  der  Wirhelthicrc  und  da^  Princip  des  Func- 
tionsivcchsds,  1875,  p.  74. 


PROBLEM   II. 


THE  NERVOUS   MECHANISM. 


"All  the  functions  of  the  nervous  system  are  as  dependent  upon  its  struc- 
ture and  nature,  as  tHe  accurate  indication  of  time  upon  the  construction  of 
the  chronometer."  —  Prochaska. 

"  Unser  Wissen  wird  nie  vollendet,  ist  und  bleibt  Stiickwerk  ;  dessen 
Erganzungdas  Streben  und  Hoflfen  der  forschenden  Denker  bleiben  wird  fiir 
alle  Zeit."  —  Radenhausen,  Osiris. 

"  Our  nimble  souls 
Can  spin  an  insubstantial  universe 
Suiting  our  mood,  and  call  it  possible, 
Sooner  than  see  one  grain  with  eye  exact, 
And  give  strict  record  of  it." 

George  Eliot,  T/ie  Spanish  Gypsy, 

"If  we  compare  the  teachings  of  our  books  with  what  Nature  is  constantly 
showing,  we  find  there  is  no  agreement  between  those  two  sources  of  learn- 
ing." —  Brown  Sequaed. 


THE  NERVOUS  MECHANISM. 


CHAPTEE    I. 

SUEVEY  OF  THE   SYSTEM. 

1.  OtJK  knowledge  of  mental  processes  is  derived  from 
reflection  on  our  personal  experiences,  combined  with  in- 
ferences from  our  observation  of  other  men  and  animals, 
under  similar  conditions.  The  processes  are  comj)lex  and 
variable ;  so  complex  and  variable,  that  knowledge  of 
their  comj)onent  factors  can  only  be  gained  through  long 
tentative  study,  aided  by  fortunate  circumstances  which 
present  these  factors  separately,  or  at  any  rate  in  such 
marked  predominance  as  to  fix  attention.  This  subjec- 
tive analysis  of  the  processes  has  to  be  supplemented  by, 
and  confirmed  by  an  objective  analysis  of,  the  conditions, 
external  and  internal :  the  facts  of  Feeling  have  to  be 
traced  to  facts  of  Physiology,  which  will  exhibit  that 
Physical  Basis  of  Mind  so  earnestly  sought  by  the 
inquirer. 

Both  the  subjective  and  the  objective  analysis  are  at 
present  in  a  very  imperfect  state.  Although  there  is 
much  confident  assertion  and  "  false  persuasion  of  knowl- 
edge "  in  both  regions,  there  is,  unhappily,  little  that  can 
be  seriously  accepted  as  demonstrated.  In  the  present 
volume  we  shall  concern  ourselves  almost  exclusively 
with  the  objective  analysis,  and  do  our  utmost  to  mark 
what  is  mere  inference  from  what  is  verified  observation. 
It  is  only  by  Observation  that  facts  can  be  settled  ;  how- 


158  THE  PHYSICAL  BASIS   OF  JIIND. 

ever  Analogy  and  Inference  may  suggest  where  the  truth 
may  lie,  they  are  finger-posts,  not  goals.  At  the  best 
they  only  tell  us  what  Observation  icoidd  reveal  could  the 
processes  be  submitted  to  Sense. 

In  a  loose  and  general  way  every  one  knows  that  the 
Xervous  System  is  a  dominant  agent  in  all  sentient  pro- 
cesses ;  although  not  by  any  means  tlie  only  agent,  yet, 
because  of  its  predominance,  it  is  artificially  accepted  as 
the  only  one.  With  the  greater  complexity  of  this  sys- 
tem, there  is  observed  a  corresponding  increase  in  the 
variety  of  sentient  phenomena.  The  labors  of  anatomists 
have  secured  a  tolerably  exact  plan  of  the  topographical 
distribution  of  this  system ;  a  somewhat  chaotic  mass  of 
observation  and  inference  passes  as  a  description  of  its 
elementary  structure.  The  labors  of  physiologists  have 
succeeded  to  a  small  extent  in  localizing  certain  functions 
in  certain  organs  of  this  system.  But  imperfect  as  our 
knowledge  of  the  elementary  structures  is,  our  knowledge 
of  the  functions  is  still  more  so.  I  wish  I  could  say 
otherwise,  and  that  I  could  ask  my  readers  to  accept  with 
confidence  what  teachers  confidently  propound.  The  atti- 
tude of  scepticism  is  always  repulsive ;  the  sceptic  is  sel- 
dom received  without  disfavor,  because  he  throws  on  us 
the  labor  of  investigation  there  where  we  wish  for  the 
confidence  of  knowledge.  Yet  it  is  only  by  facing  the 
facts  that  we  can  hope  one  day  to  solve  the  great  ques- 
tions. 

2.  The  nervous  system  has,  in  our  artificial  view  of  it, 
tw'o  divisions  :  the  Peripheral,  which  connects  the  organ- 
ism with  the  external  world ;  and  the  Central,  which  con- 
nects each  part  of  the  organism  with  all  the  other  parts. 
Although  the  system  is  constituted  by  various  tissues  — 
neural,  connective,  vascular,  and  elastic  —  it  receives  its 
characteristic  designation  from  nerve-fibrils,  nerve-fibres, 
and  nerve-cells  ;  just  as  the  muscular  system  receives  its 


THE   NEKVOUS   MECHANISM. 


159 


designation  from  contractile  cells  and  fibres.  This  neural 
tissue  assumes  three  well-marked  forms  :  1°,  nerves,  whicli 
are  bundles  of  fibres  and  fibrils,  enclosed  in  a  membra- 
nous sheath  ;  2°,  ganglia,  which  are  clusters  of  cells,  fibres, 
and  fibrils,  sometimes  enclosed  in  a  sheath,  sometimes 
not ;  o",  centres,  which  are  artificial  divisions  of  the  neural 
axis,  serving  as  points  of  union  for  different  organs. 

In  the  Invertebrata  the  neural  axis  is  the  chain  of 
ganglionic  masses  running  along  the  ventral  side,  and  giv- 
ing off  the  nerves  to  organs  of  sense,  and  to  the  muscles. 
It  may  be  seen  represented  in 
Fig.  1. 

In  the  Vertebrata  the  axis  is 
dorsal,  and  is  called  the  cerebro- 
spinal axis,  including  brain  and 
spinal  cord.  When  we  look  at 
this  structure  superficially  we 
see  various  nerves  radiating  from 
it  to  skin,  glands,  and  muscles  ; 
but  a  closer  examination,  enlight- 
ened by  knowledge  of  function, 
shows  that  some  of  these  nerves 
pass  into  it  from  the  various  sur- 
faces  and   sense-organs,  and    are  "'^^*«'i  ^'^  longitudinal  fibres, 

^         '  anil  from  the  ganglia  issue  fibres 

therefore    called    afferent  or    se7i 


Fig.  1.  —  Nervous  system  of  a 
beetle.  The  small  round  masses, 
or  ganglia,   are   seen   to   be  cen- 


to tlie  limbs,  organs  of  sense,  and 
viscera. 


sory ;  whereas  another  set  passes 
out  of  it  to  glands  and  muscles,  and  these  nerves  are 
therefore  called  efferent  or  motory.  There  are  also  fibres 
which,  passing  from  one  part  of  the  great  centre  to  an- 
other, are  called  commissural. 

To  this  brief  account  of  the  cerebro-spinal  system  may 
1)C  added  a  word  on  the  connected  chain  of  ganglia  and 
nerves  known  as  the  Sympathetic,  because  it  was  formerly 
supposed  to  be  the  organ  through  which  the  various 
"  sympathies  "  were  effected.     It  is  now  held  to  be  the 


ItJO  THE   PHYSICAL  BASIS   OF   MIND. 

system  devoted  to  the  viscera  and  blood-vessels ;  but 
there  is  still  great  want  of  agreement  among  physiologists 
as  to  whether  it  is  an  independent  system,  having  a  spe- 
cial structure  somewhat  ditferent  from  that  of  the  cerebro- 
spinal, or  whether  it  is  simply  a  great  plexus  of  nerves 
and  ganglia,  only  topographically  distinguishable  from 
the  rest  of  the  nervous  system.  Into  this  point  it  is  un- 
necessary for  me  to  enter  here.  Enough  to  say,  that  I 
entirely  agree  with  Sigmund  Mayer  in  adopting  the  sec- 
ond view.*  In  no  histological  character,  yet  specified, 
are  the  sympathetic  nerves  and  ganglia  demarcated  from 
the  others.  There  are,  indeed,  more  non-medullary  fibres 
(the  gray  fibres  of  Eemak)  in  the  sympathetic ;  but  the 
same  fibres  are  also  abundant  in  the  cerebro-spinal  sys- 
tem ;  and  the  sympathetic  has  also  its  large  medullary 
fibres. 

3.  The  Centres  are  composed  of  two  substances :  the 
gray  and  the  white.  The  gray  substance  is  often  called 
the  vesicular  because  of  its  abundant  cells ;  but  it  has 
even  more  fibres  than  cells,  and  the  wliite  substance  has 
also  a  few  cells.f  The  gray  substance  is  distributed  over 
the  surface  of  the  brain  —  in  the  convolutions  ;  and  in 
various  other  parts  of  tlie  encephalon.  It  surrounds  the 
central  canal  which  forms  the  ventricles  of  the  brain  and 
is  continued  as  a  very  small  cavity  all  down  the  spinal 
cord.  Besides  entering  into  the  important  and  conspic- 
uous masses  known  as  the  cerebral  ganglia  —  (the  optic 
thalami,  and  corpora  striata)  —  the  gray  substance  is 
massed  in  the  corpora  quadrigemina,  crura  cerebri  pons 
varolii,  and  medulla  oUongata.  We  shall  have  occasion 
to  refer  to  each  of  those  parts.  Until  modern  times  all 
the  masses  included  in  the  skull  under  the  familiar  term 

*  SiGMUXD  Mayer,  Die  2>eriplicrische  Ncrvcnzellc  %ind  die  sympathische 
NervcTisystem,  1876. 

t  On  these  cells  see  note  to  §  1 40. 


THE  NERVOUS  MECHANISM.  161 

Brain  (or  the  technical  term  Encephalon)  were  regarded 
as  the  only  centre,  and  also  as  the  origin  of  all  the  nerves. 
Nor  has  this  notion  even  yet  entirely  disappeared,  al- 
though the  spinal  cord  is  known  not  to  be  a  large  nerve 
trunk,  but  a  centre  or  connected  chain  of  centres,  struc- 
turally and  functionally  similar  to  the  cranial  centres. 
The  shadow  of  the  ancient  error  still  obscures  inter- 
pretation of  the  part  this  spinal  cord  plays  in  the  sentient 
mechanism ;  and  thus  although  the  cord  is  universally 
admitted  to  be  a  centre  for  "  sensitive  impressions," 
it  is  usually  excluded  from  Sensation.  This  widespread 
and  misleading  notion  will  be  critically  examined  in  a 
future  problem. 

4  Beginning  our  survey  of  the  cerebro-spinal  axis 
with  the  Spinal  Cord,  we  observe  it  to  consist :  1°,  of  cen- 
tral gray  substance  surrounding  the  scarcely  visible  canal, 
which  is  all  that  remains  of  the  primitive  groove  in  the 
germinal  membrane  (§  9)  ;  2°,  irregular  gray  masses, 
called  the  anterior  and  posterior  horns*  connected  with 
the  anterior  and  posterior  roots  of  the  spinal  nerves ;  and 
3°,  strands  of  white  fibres  enclosing  this  central  substance, 
and  called  the  anterior  lateral  and  posterior  columns. 

Like  the  Cerebrum,  it  is  a  double  organ  formed  by  two 
symmetrical  halves,  as  the  cerebrum  is  of  two  hemispheres. 
Each  half  innervates  the  corresponding  half  of  the  body. 
The  cord  is  unlike  the  cerebrum  in  external  form,  though 
very  like  it  in  internal  structure.  The  gray  structure  is 
mainly  external  in  the  cerebrum,  and  is  internal  in  the 
cord. 

From  the  anterior  side  of  the  cord  (that  whicli  in  ani- 
mals is  the  under  side)  the  motor  nerves  issue ;  from  the 
posterior  (in  animals  the  upper)  side,  issue  the  sensory 
nerves.    On  each  of  the  sensory  nerves  there  is  a  ganglion. 

*  These  terms  designate  the  surface  aspect  of  a  transverse  section,  of 
what  more  correctly  should  be  called  the  gray  columns.     See  Figs.  3  to  6. 


162 


THE   rUVSlCAL   BASIS    OF   MIND. 


The  roots  of  each  nerve,  formed  of  several  rootlets  issuing 
from  the  anterior  and  posterior  columns,  subsequently 
unite  together,  and  proceed  in  a  single  sheath  to  muscles 
and  skin,  separating  again,  however,  before  they  reach 
muscles  and  skin.     Fig.  2  represents  this  arrangement. 


Fig.  2.  —  A  portion  of  the  spinal  cord  iviili  its  nerves  (after  Bernard).  The  left-hand 
figure  shows  the  anterior  side  ;  the  right-liand  the  posterior.  A  the  anterior,  and  P, 
the  posterior  root,  they  meet  at  g,  the  ganglion  ;  c  and  d  are  filaments  connecting  two 
posterior  roots. 

5.  There  are  thirty-one  pairs  (sometimes  thirty-two) 
of  such  nerves  —  namely,  eight  cervical,  twelve  thoracic, 
five  lumbar,  five  sacral,  and  one  (or  two)  coccygeal.  Figs. 
3  to  6  represent  transverse  sections,  which  display  the 
entrance  of  the  roots  of  the  nerves  into  the  anterior  and 
posterior  horns. 

6.  Similar  masses  of  gray  substance  in  the  3fedulla 
Oblongata  (which  is  the  name  given  to  the  cord  when 
it  passes  into  the  skull)*  are  supposed  to  be  the  origins 
of  some  other  nerves  (the  cranial). 

*  But  this  only  in  the  higher  animals.  In  reptiles  and  amphibia  the 
medulla  descends  into  the  cer^'ical  region,  as  far  as  the  second  and  third 
cerv'ical  vervcbrae.     This  should  be  remembered  in  e.xj)erimenting. 


THE   NERVOUS   MECHANISM. 


16^ 


Fig.  3.  —  Transverse  section  of  one  half  of  the  spinal  cord  in  the  lumbar  region  (after 
Kolliker).  a,  anterior  root  eutering  tlie  anterior  gi-ay  horns,  m  and  I,  wliere  cells 
are  clustered  ;  c,  central  canal ;  d  and  e,  the  anterior  and  posterior  commissures  unit- 
ing the  two  halves  of  the  cord  ;  6,  posterior  root  entering  the  posterior  gray  horn. 


i4 


Fig.  4.  — Transverse  section  of  loth  halves  of  the  cord,  cervical  region,    a,  Fissure  sep- 
arating the  anterior  columns  ;  l>,  fissure  of  the  posterior. 


Fig,  5.  —Transverse  section  of  the  cord  in  the  dorsal  region. 


164 


THE   PHYSICAL   BASIS   OF   MIND. 


Pig.  6.  —  Transverse  section  in  the  lumbar  region. 


Although  the  Medulla  Spinalis  is  unquestionably  con- 
tinued as  the  Medulla  Oblongata,  the  arrangement  of  its 
tissues  here  becomes  gradually  changed,  and  so  compli- 
cated that  it  baffles  the  scalpel.  Anatomists  are,  however, 
agreed  on  the  one  point  of  fundamental  importance  to  us 
here  —  namely,  that  there  is  only  a  rearrangement,  not 
a  new  tissue.  Accepting  the  artificial  division  into  two 
organs,  we  may  say  that  their  functions  are  different, 
inasmuch  as  they  are  different  in  their  anatomical  con- 
nections—  they  innervate  different  parts  ;  but  as  nerve- 
centres  they  have  one  and  the  same  property. 

On  its  posterior  surface  the  Medulla  Oblongata  opens 
as  the  fourth  ventricle.  It  is  then  no  longer  a  closed 
canal,  but  an  expansion  of  the  spinal  canal,  which  is 
covered  by  the  Cerebellum.  On  its  anterior  surface  pro- 
jects the  pons  varolii.    Figs.  7  and  8  represent  these. 

While  thus  on  the  one  hand  continuing  tlie  Medulla 
Spinalis,  the  Medulla  Oblongata  is  seen  on  the  otlier  hand 
to  be  continuous  with  the  Brain  —  its  white  columns 
passing  upwards  in  the  crura  cerebri,  its  cavity  repeated 
in  the  other  ventricles.  Above  it  lie  the  ganglionic 
masses,  the  corpora  quadrigemina,  optic  thalami,  and 
corpora  striata.     Crowning  these  are  the  big  and  little 


THE  NERVOUS   MECHANISM. 


16^ 


Fig.  7.  — Back,  or  upper  view  of  the  Medulla  Oblongata  as  it  continues  the  Med.  Spi- 
nalis. 1,  Sectiou  of  tlie  thalaini  ;  2,  corpora  quadrigeiiiina  (the  two  lower  bodies  are 
imperfectly  represented  in  tlie  engraving) ;  3,  section  of  tlie  crura  cerebelli ;  4,  the 
fourth  ventricle  ;  5,  the  restiform  bodies  ;  6,  the  calamus  scriptorius. 

Pig.  8.  — Front,  or  under  view  of  the  Med.  Oblong.  1,  Optic  nerves  cut  off  at  the 
(hiasma  ;  2,  crura  cerebri ;  3,  pons  varolii ;  4,  olivary  bodies  ;  5,  anterior  pyramids  ; 
G.  spinal  columns. 

brains,  Cerebrum  and  Cerebellum.  Figs.  9  and  10  rep- 
resent this  relation  of  Medulla  Spinalis,  Medulla  Ob- 
longata, and  Brain.     Fig.  11  is  a  purely  artificial  diagram 


Fig.  9.  —  Human  Brain  in  Profile.    1 ,  Cerebnim  ;  2,  cerebellum  ;  3,  pons  varolii  and 
medulla  oblonjrata. 


166 


THE   PHYSICAL   BASIS   OF   MIND. 


which  will  give  the  reader  some  idea  of  the  disposition 
of  the  white  and  gray  substances. 


Fig.  10.  —  One  half  of  thi  Brain  in  Profile,  from  the  inside.  1,  Convolutions  of  the 
cerebrum  ;  2,  corpus  callosum  or  great  commissure  uniting  the  two  hemispheres  ;  3, 
arbor  vitae  or  branching  arrangement  of  gray  and  white  matter  in  the  cerebellum  ;  4, 
pons  varolii  and  medulla. 


Fig.  11. — Diagram  of  a  vertical  section  of  Vie  Brain  (after  Dalton).  1,  Olfactory 
ganglion  ;  2,  cerebral  hemisphere  ;  3,  corpus  striatum  ;  4,  thalamus  ;  5,  corpora  quad- 
rigemina  ;  6,  cerebellum  ;  7,  ganglion  of  the  pons  varolii ;  8,  olivary  body. 

7.    In  man  the  Cerebrum  is  to  the  Cerebellum  as  9  to 
1.      In  the  lower  vertebrates  the  preponderance  is  stiU 


THE  NERVOUS  MECHANISM.  167 

greater.  The  cerebrum  is  in  our  artificial  systems  com- 
monly divided  into  three  lobes.  The  frontal  lobe  is  that 
portion  which  lies  in  front  of  the  deep  fissure  named  after 
Rolando  ;  between  that  fissure  and  the  "internal  perpen- 
dicular fissure "  lies  the  parietal  lobe ;  behind  this  we 
have  the  occipital  lobe  ;  and,  below  the  fissure  of  Sylvius, 
the  tempero-sphenoidal  lobe.  Each  lobe  is  again  subdi- 
vided according  to  its  convolutions. 

The  'disposition  of  the  fibres  in  the  brain  is  far  too 
complex  to  be  accurately  followed.  All  that  we  can  say 
is,  that  there  are  strands  which  connect  one  convolution 
with  another,  strands  which  connect  one  hemisphere 
with  another,  strands  which  connect  cerebrum  with  cere- 
bellum, and  strands  whicli  connect  the  cerebrum  with 
the  lower  ganglia.  It  is  important  to  conceive  this  dis- 
tinctly ;  for  we  shall  hereafter  see  that  the  function  of 
the  Brain  (by  brain  is  here  meant  both  Cerebrum  and 
Cerebellum)  is  not  that  of  innervation,  but  of  incitation 
and  regulation.  To  speak  metaphorically,  it  is  the  coach- 
man wlio  holds  in  his  hands  the  reins,  and  guides  the 
team.  One  cardinal  fact  should  arrest  attention,  namely, 
that  not  a  single  nerve  in  the  body  has  its  origin  or 
centre  of  innervation  in  the  cerebrum  and  cerebellum. 
The  olfactory  and  optic  nerves  do  indeed  seem  to  issue 
from  the  cerebrum ;  and  are  commonly  described  as  cer- 
ebral nerves.  But  the  facts  of  Development,  minute 
Anatomy,  and  Experiment  prove  this  to  be  inexact. 
Although  I  shall  continue  to  speak  of  the  olfactory  and 
optic  nerves  in  accordance  with  universal  usage,  not 
wishing  to  burden  the  reader  witli  unnecessary  innova- 
tions, I  must  at  the  outset  express  my  opinion  that  these 
nerves  cannot  be  brought  under  tlie  same  general  type 
as  the  other  sensory  nerves.  Embryology  and  Anatomy 
suggest  that  they  have  no  more  claim  to  the  title  than 
the  crura  cerebri.     Of  tliis  Iiereaftcr.     Setting  these  aside, 


1G8  THE   PHYSICAL   BASIS   OF   MIND. 

no  one  now  vei'uses  to  acknowledge  that  Cerebrum  and 
Cerebellum,  although  centres  of  Incitation  and  Associa- 
tion, are  not  the  centres  of  direct  Innervation :  the  or- 
ganic mechanism  in  all  its  ^^Ayszo/o^ica/  processes  wdll 
act  independently  of  them  (so  far  as  such  artificial  dis- 
tinctions are  admissible  at  all).  This  does  not  throw 
a  doubt  on  their  inhysiologiccd  functions,  nor  on  their 
participation  in  the  normal  execution  of  physiological 
processes. 

8.  From  this  rapid  survey  two  important  points  may 
be  selected  for  special  attention.  First,  the  continuity 
of  the  neural  axis  throughout ;  secondly,  the  fundamental 
similarity  of  its  structure,  underlying  great  variations  in 
its  form  and  connections.  This,  which  is  the  anatomical 
expression  of  the  Unity  of  the  nervous  system,  will  be- 
come more  evident  after  we  have  expounded  what  Em- 
bryology and  Microscopic  Anatomy  teach.  We  may 
therefore  digress  here  awhile  to  consider 

THE  EARLY  FOKMS  OF  NERVE  CENTRES. 

9.  In  the  outermost  layer  of  the  germinal  membrane 
of  the  embryo  a  groove  appears,  which  deepens  as  its 
sides  grow  upwards,  and  finally  close  over  and  form  a 
canal.  This  canal  is  composed  of  cells  all  alike.  Its 
foremost  extremity  soon  bulges  into  three  w'ell-marked 
enlargements,  which  are  then  called  the  primitive  cerebral 
vesicles.  The  cavities  of  these  vesicles  are  continuous. 
Except  in  position  and  size,  there  are  no  discernible  dif- 
ferences in  these  vesicles,  which  are  known  as  the  Fore- 
brain,  Middle-brain,  and  Hind-brain. 

10.  The  Fore-brain  soon  buds  off  from  each  side  a 
small  vesicle.  This  is  the  oj^tic  vesicle,  the  first  rudi- 
ment of  what  subsequently  becomes  optic  nerve  and 
retina.  At  thi.-i  period  it  is  simply  a  vesicle  with  a 
hollow  stem,  the  cavity  being  continuous  with  the  cavity 


THE  NERVOUS  MECHANISM.  169 

of  the  cerebral  vesicle,  and  the  walls  continuous  with  the 
cerebral  wall. 

It  thus  appears  that  the  retina  and  optic  "  nerve  "  are 
primitive  portions  of  the  brain  —  a  detached  segment  of 
the  general  centre,  identical  in  structure  with  the  cerebral 
vesicle,  and  not  unlike  in  form.  A  cup-like  depression 
quickly  forms  the  optic  vesicle  into  an  inner  and  an  outer 
fold.  The  inner  or  concave  fold  becomes  the  retina,  and 
the  outer  or  convex  fold  (that  nearest  to  the  brain)  be- 
comes its  choroid  membrane.  On  the  fourth  day  of 
incubation  the  retina  of  the  chick  is  composed  of  spindle- 
shaped  cells,  all  alike.  On  the  seventh  day  there  is  a 
differentiation  into  layers,  one  of  which  on  the  eighth  day 
is  granular ;  on  the  tenth  two  are  granular ;  and  on  the 
thirteenth  ganglionic  cells  appear.  Some  of  the  cells 
have  elongated  into  radial  fibres  (known  as  Miiller's 
fibres) ;  and  with  the  appearance  of  rods  and  cones  the 
normal  retinal  elements  are  complete. 

11.  The  researches  of  Foster  and  Balfour*  confirm 
the  statement  that  all  the  different  parts  of  the  retina 
(whether  nervous  or  connective)  are  derived  from  one 
and  the  same  layer  of  embryonic  cells,  which  originally 
formed  a  portion  of  the  first  cerebral  vesicle. 

12.  Meanwhile  the  hollow  stem  of  this  optic  vesicle 
begins  to  develop  fibres  amidst  the  nuclei  of  its  walls. 
The  "  optic  nerve  "  arises  :  it  is  still  hollow ;  and  in  birds 
remains  so  through  life.  The  fibres  as  they  are  developed 
[jroiv  forivards  towards  the  retina,  and  spread  over  its  in- 
ternal surface.  They  also  grow  forivards  toicards  the  brain, 
and  spread  over  its  substance  ;  but  it  is  not,  as  might  be 
supposed,  and  is  generally  believed,  with  the  cerebral 
hemispheres  (or  that  portion  of  the  Fore-brain  from  which 

*  Foster  and  Balfouii,  Elcmcntu  of  Emhnjolorjij,  Part  1.,  1874.  Comp. 
ScuwALBE,  art.  Die  Retina,  in  the  Handhuch  dcr  Augenheilkunde  of 
GiiAEFK  und  Samiscii,  1871,  T.  363. 

VOL.  Ill,  8 


170  THE   PHYSICAL   BASIS   OF  MIND. 

these  are  derived),  but  with  the  IMiddle-brain  (which 
becomes  tlie  corpora  quadrigemina),  that  the  optic  fibres 
are  in  connection.* 

13.  This  will  be  understood  when  the  further  develop- 
ment is  traced.  The  Fore-brain,  after  budding  off  the  optic 
vesicles,  buds  off  two  larger  vesicles  —  the  future  cerebral 
hemispheres.  This  is  noticeable  on  the  second  day  of 
incubation,  and  by  the  third  day  each  vesicle  is  as  large 
as  the  whole  of  the  original  Fore-brain.  Their  develop- 
ment is  essentially  like  that  of  the  optic  vesicles ;  both  as 
to  the  cellular  and  the  fibrous  elements. 

The  convolutions,  corpus  callosum,  nucleus  lentiforniis, 
and  corpora  striata  are  then  indicated.  INIean while,  that 
which  originally  was  the  Fore-brain  has  lapsed  into  the 
secondary  rank  as  Intermediate-brain  {Zunsclievhirn),  and 
becomes  the  parts  surrounding  the  third  ventricle,  namely, 
the  thalami,  corpora  candicantia,  infundihuhim,  and  what 
is  called  the  "  posterior  perforated  substance." 

14.  The  MidAllc-brain,  or  Second  Vesicle,  develops  the 
corpora  quadrigemina  from  the  roof  of  its  cavity,  and  the 
crura  cerebri  from  its  floor. 

The  Hind-brain,  or  Third  Vesicle,  divides  into  two,  like 
the  First  Vesicle  ;  it  buds  off  the  hemispheres  of  the  cere- 
bellum ;  its  cavity  forms  the  fourth  ventricle  ;  its  walls 
the  medulla  oblongata. 

15.  It  thus  appears  tlmt  the  primitive  membrane  forms 
into  a  canal,  which  enlarges  at  one  part  into  three  vesicles, 
and  from  these  are  developed  the  encephalic  structures. 
The  continuity  of  the  walls  and  cavities  of  these  vesicles 
is  never  obliterated  throughout  the  subsequent  changes. 
It  is  also  traceable  throughout  the  medulla  spinalis.  And 
microscopic  investigation  reveals  that  underneath  all  the 
morphological  changes  the  walls  of  the  whole  cerebro- 

*  The  development  of  the  olfactory  lobe  and  bulb  is  similar  ;  it  need 
not  be  followed  here. 


THE  NERVOUS  MECHANISM.  171 

spinal  axis  are  composed  of  similar  elements  on  a  similar 
plan.* 

16.  Two  conclusions  directly  follow  from  this  exposi- 
tion :  —  first,  that  since  the  structure  of  the  great  axis  is 
everywhere  similar,  the  projjerties  must  he  similar;  sec- 
ondly, that  since  there  is  structural  continuity,  no  one  jpart 
can  he  called  into  activity  without  at  the  same  time  more  or 
less  exciting  that  of  all  the  rest. 

THE   PERIPHERAL   SYSTEM. 

17.  Following  the  analytical  division,  we  now  come  to 
the  Peripheral  System  of  nerves  and  ganglia.  The  separa- 
tion, I  must  often  repeat,  is  purely  artificial ;  but  the 
artifice  has  conveniences.  We  separate  in  the  same  way 
the  heart  from  veins  and  arteries,  and  the  capillary  cir- 
culation from  the  arterial. 

Each  nerve  has  its  direct  connection  with  a  particular 
centre,  and  indirectly  with  the  whole  system.  It  has  its 
circumscribed  territory,  and  individual  office.  Except  in 
a  few  cases  of  anastomosis,  the  action  of  one  nerve  does 
not  involve  that  of  another :  only  one  muscle  or  one 
group  of  muscles  is  moved,  without  exciting  motion  in  a 
neiglibor.  It  is  through  the  centres  that  these  individual 
territories  are  united ;  and  a  wave  of  excitation  always 
passes  throughout  the  central  substance.  Thus  the  cen- 
tres are  not  simply  organs  of  association,  consequently  of 

*  German  anatomists  divide  this  axis  into  trunk  and  crown  {Hirn- 
■stamm  and  Hirnmantd).  There  is  convenience  in  this  division.  If  we 
remove  all  the  gray  matter  of  the  cerebrum,  with  all  the  white  matter 
radiating  from  it,  until  we  again  come  upon  gray  matter—  and  if  we  then 
cut  the  cerebellum  from  its  descending  strands  of  white  matter  —  we  shall 
liave  removed  the  crown,  and  leave  the  trunk  remaining.  This  tnink  is 
lonstituted  by  the  corpora  striata,  nucleus  lentiforniis,  optic  thalami,  cor- 
pora quadrigemina,  crura  cerebri,  pons,  medulla  oblongata,  and  medulla 
spinalis.  From  this  trunk  all  the  organs  of  the  body  are  directly  inner- 
vated (except  those  innervated  fiom  th(!  sympathetic  ?). 


172  THE  PHYSICAL  BASIS   OF  MIND. 

legulation,  but  are  the  nexus  whereby  the  diversity  of  the 
actions  is  integrated  into  the  unity  of  consensus. 

18.  Nothing  further  need  at  present  be  stated  respect- 
ing the  nerves ;  but  it  is  needful  to  give  precision  to  the 
ideas  of 

GANGLIA   AND    CENTEES, 

usually  spoken  of  as  if  they  were  convertiljle  terms.  That 
this  is  inexact  may  be  readily  shown,  and  that  it  is  mis- 
leading appears  in  its  causing  physiologists  to  credit 
every  ganglion,  wherever  found,  with  central  functions ; 
and,  by  an  almost  inevitable  extension  of  the  error,  has 
led  to  the  assignment  of  central  functions  to  a  single 
ganglionic  cell !  This  is  but  part  of  that  "  superstition 
of  the  cell "  against  which  I  shall  have  to  protest.  I  will 
not  here  raise  the  doubt  which  presses  from  various  sides 
respecting  the  central  functions  oi  the  ganglia  in  the 
heart  and  intestines,  because  the  reader  perhaps  shares 
the  general  opinion  on  that  point ;  but  let  me  simply  ask 
what  central  function  can  possibly  be  assigned  to  the 
ganglia  on  each  of  the  spinal  sensory  nerves  ?  above  all  to 
those  grouped  and  scattered  ganglionic  cells  w^hich  are 
found  at  the  peripheral  termination  of  some  nerves,  and 
in  the  very  trunks  of  others  ?  There  may,  indeed,  be 
imagined  a  central  function  for  the  ganglia  in  the  mesen- 
tery, and  even  in  tlie  choroid  coat  of  the  retina,  on  the 
hypothesis  (quite  gratuitous,  I  think)  of  their  regulating 
the  circulation ;  but  even  this  explanation  cannot  be 
adopted  with  respect  to  the  ganglionic  cells  which  appear 
in  the  course  of  the  nerve.* 

*  "On  s'est  preoccupe  du  role  special  que  pouvaient  jouer  les  gangli- 
ons peripheriques  situes  dans  le  voisinage  de  certaines  organes  ;  et  on  a 
ju'etendu  que  les  nerfs  ne  jouissaient  de  leur  propriete  d'agir  sur  ces 
iirganes  qu'apres  avoir  traverse  ces  ganglions.  On  avait  admis  que  I'exci- 
tation  portee  sur  le  filet  nerveux  avant  son  entre  dans  le  ganglion  lestait 
.sans  effet ;  que  pour  obtenir  Taction  excitatrice  des  fonctions  de  Torgam' 
il  fallait  exciter  le  nerf  entre  lui  et  le  ganglion  voisin."- — Claude  Ber- 


THE   NEKVOUS   jNIECHANISM.  173 

The  meaning  of  a  physiological  centre  is,  that  it  is  a 
point  to  which  stimulations  proceed,  and  from  which  they 
are  reflected.  The  meaning  of  a  ganglion  is,  that  it  is  a 
group  of  nerve  cells  dispersed  among,  or  in  continuation 
with,  nerve  fibres :  it  may  be  a  centre  of  reflection,  or  it 
may  not ;  and  in  the  latter  case  its  physiological  office  is 
at  present  undetermined.  A  ganglion  is  no  more  a  centre 
in  virtue  of  its  cell-group  tlian  a  muscle  is  a  limb.  All 
function  depends  on  connection,  and  central  function  de- 
mands a  connection  of  afferent  and  efferent  parts. 

19.  The  ganglia  found  in  the  ventral  cord  of  the  Inver- 
tebrate (see  Fig.  1)  are  centres,  each  of  which  has  consid- 
erable independence,  each  regulating  a  single  segment  of 
the  body,  or  a  group  of  similar  segments.  As  the  scale 
of  animal  complexity  ascends,  these  separated  centres  tend 
more  and  more  to  coalesce,  and  with  this  coal^escence 
comes  an  increasing  comhination  of  movements.*  Ob- 
serve the  caterpillar  slowly  crawling  over  a  leaf;  each 
segment  of  its  body  moves  in  succession ;  but  when  this 
caterpillar  becomes  a  butterfly  the  body  moves  rapidly, 
and  all  at  once.  Open  the  caterpillar,  and  you  find  its 
nervous  centres  are  thirteen  separate  ganglia,  each  presid- 
ing over  a  distinct  part  of  the  body,  and  each  capable  of 

NARD,  Sijsfemc  Nerveux,  II.  169.  But  on  proceeding  to  verify  these 
statements  by  experiment,  Bernard  is  led  to  the  conchision,  "que  h- 
ganglion  n'a  pas  d'influence  propre  sur  lo  mode  de  I'excitatiou  transmise 
a  I'organe." 

I  was  delighted  to  find  my  opposition  to  the  current  teaching  respect- 
ing the  central  functions  of  ganglionic  cells  thoroughly  borne  out  by  the 
elaborate  researches  of  Sigmund  Maykh  {Archiv  fiir  Psijchiatric,  Bd.  VI. 
Heft  2).  Having  artificially  produced  such  cells,  he  j'Prtinently  asks, 
How  can  we  attribute  central  functions  to  cells  which  appear  in  tlie  pro- 
cess of  regeneration  of  a  divided  nerve  ?  The  error  has  its  origin  in  tlu; 
confusion  of  functions  with  jiroperties. 

*  It  is  often,  though  incorrectly,  stated  that  every  segment  of  an 
annulose  animal  has  its  separate  ganglion.  Tlic  fact  is,  that  while  the 
ganglia  are  usually  fewer  than  the  segments,  they  are  sometimes  more 
numerous. 


174  THE   rilYSICAL   BASIS   OF   MIND. 

independent  action.  Open  the  butterfly,  and  you  find  tlie 
thirteen  ganglia  greatly  changed:  the  second  and  third 
are  fused  into  one ;  the  fourth,  fifth,  and  si.xth  into 
another;  the  eleventh  and  twelfth  into  anotlier ;  the  only 
trace  of  the  original  separation  is  in  a  slight  constriction 
of  the  surface.  The  movements  of  tlie  caterpillar  were 
few,  simple,  slow,  and  those  of  the  butterfly  are  many, 
varied,  and  rapid. 

20.  In  the  Vertebrates  the  coalescence  of  oanalia  is 
such  that  the  spinal  axis  is  one  great  centre.  "We  do 
indeed  anatomically  and  physiologically  subdivide  it  into 
several  centres,  because  several  portions  directly  innervate 
separate  organs ;  but  its  importance  lies  in  the  intimate 
blending  of  all  parts,  so  that  Jluduating  combinations  of 
its  elements  may  arise,  and  varied  movements  result. 
Eacli  centre  combines  various  muscles ;  the  axis  is  a  com- 
bination of  centres.  The  brainless  frog,  for  instance,  has 
still  the  spinal  cord,  and  therefore  the  power  not  only  of 
moving  either  of  his  limbs,  but  also  of  combining  their 
separate  movements  :  if  grasped,  he  struggles  and  escapes  ; 
if  pricked,  he  hops  away.  But  these  actions,  although 
complex,  are  much  less  complex  and  varied  than  the  ac- 
tions of  the  normal  frog. 

There  is  not  only  a  coalescence  of  ganglia,  but  a  greater 
and  greater  concentration  of  the  substance  in  the  upper 
portions  of  the  axis.  In  the  inferior  vertebrates,  and  in 
the  mammalian  embryo,  the  spinal  cord  occupies  the 
whole  length  of  the  vertebral  canal  from  the  head  to  the 
tip  of  the  tail ;  and  here  the  centres  of  reflexion  corre- 
spond with  the  several  segments.  But  as  the  cranial 
mass  develops  there  is  a  withdrawal  of  neural  substance 
from  the  lower  parts,  and  the  centres  of  reflexion  are  then 
some  way  removed  from  the  segments  they  innervate.  In 
the  animal  development  there  is  even  a  greater  and 
gi'eater  predominance  of  the  upper  portions,  so  that  the 


THE  NEKVOUS  MECHANISM.  175 

brain  and  medulla  oblongata  are  of  infinitely  more  impor- 
tance than  the  spinal  cord. 

21.  Besides  the  central  group  of  elements  which  belong 
to  fixed  and  definite  actions,  we  must  conceive  these  ele- 
ments capable  of  variable  combinations,  like  the  pieces 
of  colored  glass  in  a  kaleidoscope,  which  fall  into  new 
groups,  each  group  having  its  definite  though  temporary 
form.  The  elements  constitute  really  a  continuous  net- 
work of  variable  forms.  It  is  to  such  combinations,  and 
not  to  fixed  circumscribed  ganglia,  that  we  must  refer  the 
subordinate  centres  of  the  axis.  We  speak  of  a  centre 
for  Eespiration,  a  centre  for  Laughing,  a  centre  for  Cry- 
ing, a  centre  for  Coughing,  and  so  on,  with  as  much  pro- 
priety as  we  speak  of  a  centre  for  Swallowing  or  for 
Walking.  Not  that  in  these  cases  there  is  a  circumscribed 
mass  of  central  substance  set  apart  for  the  innervation  of 
the  several  muscles  employed  in  these  actions,  and  for  no 
other  purpose.  Each  action  demands  a  definite  group  of 
neural  elements,  as  each  geometric  form  in  the  kaleido- 
scope demands  a  definite  group  of  pieces  of  glass ;  but 
these  same  pieces  of  glass  will  readily  enter  into  other 
combinations ;  and  in  like  manner  the  muscles  active  in 
Respiration  are  also  active  in  Laughing,  Coughing,  etc., 
though  differently  innervated  and  co-ordinated. 

22.  The  physiological  rank  of  a  centre  is  therefore  the 
expression  of  its  power  of  fluctuating  combination.  The 
medulla  oblongata  is  higher  than  the  medulla  spinalis, 
because  of  its  more  varied  combinations  ;  the  cerebrum  is 
liigher  than  all,  because  it  has  no  fixed  and  limited  com- 
binations. It  is  the  centre  of  centres,  and  as  such  the 
supreme  organ. 


176 


THE   PHYSICAL  BASIS   OF  MIND, 


CHAPTEE    II. 

THE  FUNCTIONAL  RELATIONS  OF  THE  NERVOUS  SYSTEM. 

23.  The  distinguishable  parts  of  this  system  are  the 
central  axis,  the  cranial  nerves,  and  the  spinal  nerves,  with 
the  chain  of  ganglia  and  nerves  composing  the  Sympa- 
thetic. Let  us  briefly  set  down  what  is  known  of  their 
special  offices. 

Men  very  early  discovered  that  the  nerves  were  in  some 
way  ministrant  to  Sensation  and  Movement ;  a  divided 
nerve  always  being  accompanied  by  insensibility  and  im- 
mobility in  the  limb.  Galen,  observing  tliat  paralysis  of 
movement  sometimes  occurred  without  insensibility,  sug- 
gested that  there  were  two  kinds  of  nerve ;  but  no  one 


Fig.  12.  —  Tyansverse  sections  of  spinal  cord  (dorsal  region). 


THE  NEEVOUS  MECHANISM.  17/ 

was  able  to  furnish  satisfactory  evidence  in  support  of 
this  suggestion  until  early  in  the  present  century,  when 
the  experiments  of  Charles  Bell,  perfected  by  those  of 
Majendie  and  Mtiller,  placed  the  suggestion  beyond  dis- 
pute. 

24.  Fig.  12  is  a  diagram  (not  a  drawing  of  tlie  actual 
aspect,  which  would  be  hardly  intelligible  to  readers  un- 
versed in  such  matters)  representing  two  transverse  sec- 
tions of  the  spinal  cord  just  where  the  nerve-roots  issue. 
The  gray  substance  is  somewhat  in  the  form  of  a  rude  H, 
in  the  dorsal  region,  and  of  the  expanded  wings  of  a  butter- 
Hy  in  the  lumbar  enlargements  (Figs.  4  -  6) ;  the  extrem- 
ities of  this  gray  substance  are  the  anterior  and  posterior 
horns.  We  have  already  said  that  from  the  anterior  horns 
of  each  half  issue  the  roots  of  the  motor  nerves,  which 
pass  to  the  muscles.  From  the  posterior  horns  issue  the 
sensory  nerves,  which,  soon  after  leaving  the  cord,  enter 
the  ganglia  before  joining  the  motor  nerves,  and  then  pass 
to  the  skin,  in  the  same  sheath  with  their  companions, 
separating  again  as  tliey  reach  the  muscles  and  surfaces 
where  they  are  to  be  distributed.  When  this  mixed  nerye 
is  cut  through,  or  tied,  all  sensation  and  movement  disap- 
pear from  the  parts  innervated.  But  if  only  one  of  the 
roots  be  cut  through,  above  the  ganglion,  there  will  then 
be  only  a  loss  of  movement  or  a  loss  of  sensation.  Thus 
suppose  the  section  be  made  at  a,  h,  A :  we  have  then 
divided  a  sensory  nerve,  and  no  pinching  or  pricking  of 
the  part  innervated  by  that  nerve  wull  be  felt ;  but  move- 
ment will  take  place  if  the  under  nerve  be  irritated,  or  if 
a  sensation  elsewhere  be  excited.  Now  reverse  the  experi- 
ment, as  at  B,  c,  r/.  Then,  pricking  of  the  skin  will  be 
felt,  but  no  movement  will  respond.  The  nerve  wliich 
enters  the  cord  at  the  upper  (posterior)  part  is  therefore  a 
sensory  nerve ;  that  which  enters  at  the  under  (anterior) 
])art  is  motor.     The  direction  is  in  each  case  indicated  by 


178  THE  PHYSICAL  BASIS   OF   MIND. 

the  arrow.  The  central  end  h,  if  irritated,  will  produce 
sensation ;  whereas  the  peripheral  end  a  produces  neither 
sensation  nor  movement.  The  central  end  d  produces 
neither  sensation  nor  movement ;  the  peripheral  end  c 
produces  mo\'ement. 

25.  Two  facts  are  proved  by  these  experiments.  First, 
that  the  co-oi:)eration  of  the  centre  is  necessary  for  Sensa- 
tion, but  not  for  Movement.  Althouj^h  normally  all  the 
muscles  of  the  trunk  are  moved  only  when  their  centre 
has  been  excited,  yet  any  irritation  applied  directly  to  the 
muscle  nerve,  even  when  separated  from  its  centre,  pro- 
duces a  movement.  And  to  this  we  may  add  that  a 
slighter  stimulus  will  move  the  muscle  by  direct  irrita- 
tion of  the  nerve,  than  by  indirect  irritation  through  the 
centre ;  a  slighter  stimulus  also  will  suffice  when  applied 
to  the  nerve  than  wlien  applied  to  the  muscle  itself. 

26.  The  second  fact  proved  is  known  as  BclFs  Law, 
that  the  sensor}^  and  motor  channels  are  respectively  the 
posterior  and  anterior  nerves.  The  fact  is  indisputable, 
but  its  theoretic  interpretation  can  no  longer  be  accepted 
in  its  original  form.  Bell  supposed  tlie  two  nerves  to  be 
different  in  kind,  endowed  with  different  specific  energies, 
the  one  sensitive,  the  other  motor.  The  majority  of  writ- 
ers still  express  themselves  as  if  they  adopted  this  view. 
We  shall,  however,  presently  see  reason  for  replacing  it 
by  the  more  consistent  interpretation  which  assigns  one 
and  the  same  property  to  both  nerves,  marking  their  dis- 
tinction by  the  terms  afferent  and  efferent ;  the  one  set 
being  anatomically  so  disposed  that  it  conveys  stimuli 
from  the  surfaces  to  the  centre,  and  the  other  set  convey- 
ing stimuli  from  the  centre  to  the  muscles,  glands,  and 
other  cells.* 

*  It  has  been  proved  that  the  cells  of  the  cornea  and  the  pigment  cells 
of  the  skin  contract  under  nervous  excitation.  We  cannot  suppose  that 
although  these  are  the  only  cells  which  have  hitherto  been  brought  under 


THE  NERVOUS  MECHANISM.  179 

27.  Bell's  discovery  was  rapidly  generalized.  The 
principle  of  localization  was  extended  to  all  nerves,  and 
of  course  to  the  posterior  and  anterior  columns  of  the 
spinal  cord,  which  indeed  were  assumed  to  be  continua- 
tions of  the  nerves.  Bell,  who  was  greater  as  an  anato- 
mist than  as  a  philosopher,  always  maintained  that  ana- 
tomical deduction  was  superior  to  experiment.  But  this 
was  to  misunderstand  the  reach  of  deduction,  which  is 
only  valid  to  the  extent  of  its  premises.*  In  the  present 
case,  the  premises  assumed  that  the  posterior  columns 
were  continuations  of  the  posterior  roots,  and  carried 
impressions  to  the  brain,  the  anterior  columns  carrying 
back  from  the  brain  the  "  mandates  of  the  will."  Exper- 
iment lias,  however,  decisively  shown  that  it  is  not  through 
the  posterior  columns  that  sensory  impressions  travel  to 
the  brain,  but  through  the  central  gray  substance. 

28.  The  spinal  cord  with  its  central  gray  substance  is 
at  each  point  a  centre  of  reflexion.  Connected  as  it  is 
with  different  organs,  we  artificially  consider  it  as  a  chain 
of  different  centres,  and  try  to  detect  the  functional  rela- 
tions of  its  parts.  The  inquiry  is  important,  but  we 
must  bear  in  mind  the  cardinal  principle  that  diversity  of 
Function  depends  on  the  organs  innervated,  and  not  on  a 
diversity  of  Property  in  the  nervous  tissue.  Although 
all  nerves  have  a  common  structure  and  common  prop- 
erty, yet  we  distinguish  them  as  sensory  and  motor ;  and 
the  sensory  we  subdivide  into  tliosc  of  Special  Sensation 
and  those  of  Systemic  Sensation.  The  motor  we  divide 
into  muscular,  vasomotor,  and  glandular.  The  hypothesis 
of  specific  energies  must  be  relinquished  (§  63). 

experimental  okservation,  they  arc  the  only  cells  .subject  to  nerve-influ- 
ence.    We  may  safely  assume  tliat  wheiever  a  nerve-fibre  terminates,  its 
action  will  be  transformed  into  an  excitation  of  the  part.     Habitually, 
however,  motor-nerves  are  spoken  of  as  muscle-nerves. 
*  On  Deduction,  see  Problems :  First  Series,  Vol.  II.  p.  159 


180  THE   PHYSICAL   BASIS   OF    MIND. 

In  like  manner  all  centres  have  a  common  structure 
and  a  common  property,  M'ith  a  great  diversity  of  func- 
tional relations.  Here  also  the  hypothesis  of  specific 
energies  has  been  generally  adopted,  owing  to  a  mistaken 
conception  of  the  biological  principle  just  mentioned. 
The  cerebral  hemispheres  are  credited  with  the  properties 
of  sensation,  thought,  and  volition  ;  the  cerebellum  with 
the  property  of  muscular  co-ordination  ;  the  spinal  cord 
with  the  property  of  reflexion. 

29.  No  attempt  to  assign  the  true  functional  relations 
of  the  centres  will  be  made  at  the  present  stage  of  our 
exposition.  We  must  learn  more  of  the  processes  in  Sen- 
sation, Thought,  and  Volition,  before  we  can  unravel  the 
complex  physiological  web  on  which  they  depend.  But 
here,  provisionally,  may  be  set  down  what  observation 
and  experiment  have  disclosed  respecting  the  part  played 
by  certain  centres.  We  know,  for  example,  that  when 
the  cerebral  hemispheres  are  carefully  removed  from  a 
reptile  or  a  bird,  all  the  essentially  vital  functions  go  on 
pretty  much  as  before,  but  a  great  disturbance  in  some 
of  the  psychical  functions  is  observed.  The  brainless  bird 
eats,  drinks,  sleeps,  moves  its  limbs  separately  and  in 
combination,  manifests  sensibility  to  light,  sound,  and 
touch,  performs  such  instinctive  actions  as  preening  its 
feathers,  or  thrusting  the  head  under  the  wing  while 
roosting.  Throw  it  into  the  air  and  it  will  fly.  In  its 
flight  it  will  avoid  obstacles,  and  will  alight  upon  a  ledge, 
or  your  shoulder.  But  it  will  not  fly  unless  thrown  into 
the  air ;  it  will  not  escape  through  the  open  door  or  win- 
dow ;  it  will  avoid  objects,  but  will  show  no  fear  of  them, 
—  alighting  on  your  head,  for  example,  without  hesita- 
tion. It  is  sensitive  to  light,  and  may  in  a  certain  sense 
be  said  to  see;  but  it  fails  to  ijerccive  what  is  seen.  It  will 
eat  and  drink,  if  food  and  water  be  administered,  but  it 
will  starve  near  a  heap  of  grain  and  never  peck  it,  not 


THE  NERVOUS  MECHANISM.  181 

even  if  the  beak  be  thrust  into  the  heap.  A  grain,  or 
•strip  of  meat,  may  be  thrust  inside  the  beak ;  there  it  will 
remain  unswallovved,  unless  it  touches  the  back  of  the 
mouth,  then  swallowing  at  once  follows  the  stimulus. 
The  bird  u-itli  its  brain  will  fly  away  if  you  turn  the 
linger,  or  stick,  on  which  it  is  perching ;  without  its 
l)rain,  it  makes  no  attempt  to  fly,  but  flutters  its  wings, 
and  balances  itself.  If  you  open  the  mouth  of  a  cat,  or 
rabbit,  and  drop  in  some  bitter  fluid,  the  animal  closes  its 
mouth  firmly,  and  resists  your  efforts  to  repeat  the  act ; 
without  its  brain,  the  animal  shows  the  same  disgust 
at  the  taste,  but  never  resists  the  preliminaries  of  the 
repetition. 

30.  These,  and  analogous  facts,  have  been  noted  by 
various  experimenters.  They  are  very  far  from  proving 
what  is  usually  concluded ;  but  they  prove  the  important 
negative  position  that  the  cerebrum  is  not  the  centre  of 
innervation  for  any  of  the  organs  on  which  the  observed 
actions  depend.  Thus,  the  cerebrum  is  not  necessary  to 
sight:  ergo  it  does  not  innervate  the  eye.  It  is  not  neces- 
sary to  hearing :  ergo  it  does  not  innervate  the  ear.*  It 
is  not  necessary  to  breathing,  swallowing,  flying,  etc. : 
ergo  it  does  not  innervate  the  organs  of  these  functions. 

What  then  is  lost?  We  have  only  to  remember  that 
the  cerebrum  is  continuous  with  the  thalami  and  corpora 
striata,  and,  through  its  crura,  with  the  medulla  oblon- 
gata and  medulla  spinalis,  to  foresee  that  its  removal 
must  more  or  less  affect  the  whole  neural  axis,  and  con- 
sequently disturb  the  actions  of  the  whole  organism ;  this 
disturbance  w^ll  often  have  the  appearances  which  would 

*  I  do  not  here  touch  upon  tlie  question  as  to  whetliev  these  actions 
of  the  senses  are  sensations,  because  that  (juestion  deuiands  that  we  should 
lirst  settle  what  is  Sensation.  I  may  at  once,  however,  say  that  what  is 
ordinarily  understood  as  a  sensation  of  color,  or  a  sensation  of  sound,  is, 
in  my  opinion,  not  possible  without  the  cerebrum.  But  the  sensibility 
of  the  eye  and  ear  is  manifestly  preserved. 


182  THE   PHYSICAL   BASIS    OF   MIND. 

be  due  to  the  removal  of  a  central  a}iparatus,  so  that  we 
shall  be  apt  to  attribute  the  cessation  of  a  lunction  to  the 
loss  of  its  organ,  when  in  fact  the  cessation  is  due  simply 
to  an  arrest  of  the  organ  by  irritation.  Thus  the  cessa- 
tion of  consciousness,  or  of  any  particular  movements, 
when  the  cerebrum  is  removed,  is  no  decisive  proof  that 
the  cerebrum  is  the  organ  of  consciousness,  or  of  the 
movement  in  question.  This  point  will  be  duly  con- 
sidered hereafter.  "What  we  have  now  to  consider  is  the 
facts  observed  after  removal  of  the  cerebrum. 

First,  we  observe  a  loss  of  that  power  of  combining 
present  states  with  past  states,  present  feelings  with  feel- 
ings formerly  excited  in  conjunction  with  them,  the 
power  which  enables  the  animal  to  adjust  its  actions 
to  certain  sensations  7iou-  unfdt  but  which  icill  he  felt  in 
consequence  of  the  adjustment.  Secondly,  we  observe  a 
loss  of  Spontaneity :  the  bird,  naturally  mobile  and  alert, 
now  sits  moveless  for  hours  in  a  sort  of  stupor,  occasion- 
ally preening  its  feathei"s,  but  rarely  quitting  its  resting- 
place.  All  the  most  conspicuous  phenomena  which  we 
assign  to  Intelligence  and  "Will  seem  alisent.  The  sen- 
sations are  altered  and  diminished.  Many  Instincts  have 
disappeared,  but  some  remain.  The  sexual  feeling  is 
preserved,  although  the  bird  has  lost  all  power  of  direct- 
ing its  actions  so  as  to  gratify  the  desire.  But  these 
effects  are  only  observ^ed  when  the  whole  of  both  hemi- 
spheres have  been  removed.  If*  a  small  portion  remain 
the  bird  retains  most  of  its  faculties,  though  with  less 
energy.  In  frogs  and  fishes  there  is  little  discernible 
effect  observed  when  a  large  portion  of  the  cerebrum  is 
removed. 

31.  Xow  take  away  from  this  mutilated  bird  its  cere- 
bellum :  all  the  functions  continue  as  before  except  that 
some  combined  movements  can  no  longer  be  effected ; 
flight  is  impossible  ;  walking  is  a  mere  stagger.     Remove 


THE  NERVOUS  MECHANISM.  183 

only  the  lateral  lobes,  and  though  flight  is  still  possible 
great  incoherence  of  the  wings  is  observed,  whereas  walk- 
ing is  not  much  affected.  If  only  the  cerebellum  be 
removed,  the  cerebrum  being  intact,  the  phenomena  are 
very  different.  All  the  perceptions  and  almost  all  the 
emotions,  all  the  spontaneity  and  vivacity  are  retained ; 
but  tlie  sexual  instinct,  which  was  manifested  when  the 
cerebrum  was  removed,  is  now  quite  gone.  What  we 
call  Intelligence  seems  unaffected.  The  bird  hears,  and 
understands  the  meaning  of  the  sounds,  sees  and  per- 
ceives, sees  and  fears,  sees  and  adjusts  its  movements 
with  a  mental  vision  of  unseen  consequences.* 

32.  Are  we  from  these  facts  to  conclude  tliat  the  cere- 
brum is  the  "organ  of  the  mind";  that  it  is  "the  seat" 
of  sensation,  thought,  emotion,  volition;  and  that  the  cere- 
bellum is  the  "  seat "  of  the  sexual  instinct,  and  muscular 
co-ordination  ?  Such  conclusions  have  found  acceptance, 
even  from  physiologists  who  would  have  been  startled 
had  any  one  ventured  to  affirm  that  the  medulla  oblon- 
gata was  the  "  organ  "  of  Eespiration,  because  Eespiration 
ceases  when  this  centre  is  destroyed.  I  shall  have  to 
combat  this  notion  at  various  stages  of  my  exposition. 
Here  let  me  simply  say  that  it  is  irreconcilable  with  any 
clear  conception  of  organ  and  function  ;  and  is  plainly 
irreconcilable  with  any  survey  of  })sychical  phenomena 
in  animals  in  whom  the  cerebrum  does  not  exist,  and 
in  animals  from  whom  it  has  been  removed. 

What  the  facts  indisputably  prove  is  that  the  cere- 
Ijrum  has  an  important  part  in  the  mechanism  by  which 
the  most  complex  psychical  combinations  are  effected, 
and  that  the  cerebellum  has  an  important  part  in  the 
mechanism  by  which  the  most  complex  muscular  com- 

*  It  has  been  ob.serve(l  that  removal  of  the  cerebellum  affects  the  pig- 
ment cells  of  the  skin.  No  doubt  other  parts  are  also  affected,  but  the 
changes  have  hitherto  escaped  observation. 


184  THE   PHYSICAL   BASIS   OF   MIND. 

lunations  are  effected.  Tlic  su})renie  importance  of  the 
cerebrum  may  be  inferred  from  its  dominating  all  the 
other  centres,  and  from  its  preponderance  in  size.  In 
man  it  stands  to  all  the  other  cranial  centres  together  in 
the  relation  of  11  to  3.  It  is  about  five  times  as  heavy 
as  the  spinal  cord  —  that  is  to  say  from  1,100  to  1,400 
granunes,  compared  with  27  to  30  grammes.  The  quan- 
tity of  blood  circulating  through  it  is  immense.  Haller 
estimated  the  cranial  circulation  as  one  fifth  of  the  whole 
circulation.  If,  therefore,  the  Nervous  Centres  are  agents 
in  the  production  of  Sensation  and  Intelligence,  by  far 
tlie  largest  share  must  be  allotted  to  the  cranial  centres, 
and  of  these  the  largest  to  the  Cerebrum. 

33.  It  is,  however,  one  thing  to  recognize  the  Cere- 
brum as  having  an  important  part  in  the  production  of 
psychical  phenomena,  another  thing  to  localize  all  the 
phenomena  in  it  as  their  organ  and  seat  —  a  localization 
which  soon  beciomes  even  more  absurd,  when  of  all  the 
cerebral  structure  the  multipolar  cells  alone  are  admitted 
as  the  active  agents  ! 

As  was  said  just  now,  we  recognize  in  the  Medulla 
Oblongata  the  nervous  centre  of  Eespiration,  but  we  do 
not  suppose  that  Eespiration  has  its  seat  there,  nor  that 
this  centre  is  absolutely  indispensable  for  the  essential 
part  of  the  process.  We  respire  by  our  skin,  as  well  as 
by  our  lungs ;  many  animals  respire  who  have  nothing 
like  a  medulla  oblongata ;  as  many  animals  feel,  and 
manifest  will,  who  have  nothing  like  a  cerebrum.  The 
destruction  of  centres  is  of  course  a  disturbance  of  the 
mechanisms  which  they  regulate.  But  even  the  observed 
results  of  a  destruction  require  very  close  examination, 
and  are  liable  to  erroneous  interpretations.  The  disap- 
pearance of  a  function  following  the  destruction,  or  disease 
of  a  particular  part,  is  not  to  be  accepted  as  a  proof  that 
this  part  is  the  organ  of  the  lost  function ;  because  pre- 


THE  NERVOUS  MECHANISM.  185 

cisely  the  same  phenomena  may  often  be  observed  follow- 
ing the  destruction  of  a  totally  different  part.*  But  one 
result  may  always  be  relied  on,  and  that  is  the  j^rsistcncc 
of  a  function  after  removal  of  a  particular  part.  Thus 
there  is  a  certain  spot  of  the  cerebral  convolutions  from 
which  movements  of  the  limbs  are  excited  when  the 
electrodes  are  applied  to  it ;  removal  of  the  substance  is 
immediately  followed  by  paralysis  of  the  limbs.  Are 
we  to  conclude  that  this  spot  is  the  organ  of  the  func- 
tion ?  It  is  true  that  the  function  is  called  into  action 
by  a  stimulus  applied  to  this  spot :  true  that  the  func- 
tion suddenly  vanishes  when  the  substance  of  this  spot 
is  destroyed.  Nevertheless,  what  seems  a  loss  of  func- 
tion is  only  a  disturbance.  In  two  or  three  days  the 
paralysis  begins  to  disappear,  and  at  the  end  of  a  week 
the  limbs  are  moved  nearly  in  the  normal  manner.  And 
the  same  is  true  when  tlie  spot  in  question  is  destroyed 
on  both  sides.  The  recovery  of  the  function  shows  that 
the  absent  part  was  not  its  organ.  There  is  a  paradoxical 
experiment  recorded  by  M.  Paul  Bert  which  may  be  cited 
here.  He  removed  the  right  cerebral  hemisphere  from  a 
chameleon,  and  found  that  the  limbs  on  the  left  side  were 
paralyzed ;  but  on  liis  then  removing  the  left  cerebral 
hemisphere  the  limbs  of  the  left  side  recovered  their 
activity.  A  similar  result  was  obtained  by  Lussana  and 
Lemoigne  by  extirpation  of  tlie  thalami.  When  we  find 
combined  movements  persisting  after  the  cerebellum  has 
been  destroyed,  we  may  be  sure  that  the  cerebellum  is 

*  OwsJANNiKOW  describes  the  results  of  removing  carefully  the  cra- 
nial ganglia  of  the  crayfish  ;  and  these  effects  Mfa'ER  observes  to  be  iden- 
tical with  those  which  follow  removal  of  the  large  claw  of  the  crayfish  ! 
A.  B.  Meyer,  Das  Jlcmmungsnerven-si/stem  dcs  Herzcns,  1869,  p.  23. 
Let  me  add  that  the  jilienomena  described  by  M.  Faivre  as  following  the 
destruction  of  one  subrjesojjhagcal  ganglion  in  the  Dytiscxis,  are  so  little 
to  be  referred  to  the  mere  absence  of  the  ganglion,  that  I  find  them  not 
to  occur  when  the  whole  head  is  removed. 


ISG  THE   PIIYSIC.U,   BASIS   OF   MIND. 

not  tlie  organ  by  which  such  combinations  take  place  ;  and 
when  we  find  sensation  and  volition  manifested  after  the 
cerebrum  has  been  removed,  we  may  be  sure  that  the  cere- 
brum is  not  the  organ  ibr  these  sensations  and  volitions. 

34.  And  this  we  do  find.  Physiologists,  indeed,  for 
the  most  part,  deny  it ;  or  rather,  while  they  admit  the 
observed  facts,  they  refuse  to  admit  the  only  consistent 
interpretation,  biassed  as  they  are  by  the  traditional  con- 
ception of  the  brain.  After  having  for  many  years  per- 
sistently denied  Sensibility  to  any  centre  except  the  cere- 
brum, they  are  now  generally  agreed  in  including  the 
medulla  oblongata  within  the  privileged  region;  but  they 
still  exclude  the  medulla  spinalis. 

35.  If  all  the  cranial  centres  as  far  as  the  medulla 
oblongata  are  removed  from  young  rabbits,  dogs,  or  cats, 
there  are  unmistakable  evidences  of  Sensibility  in  their 
cries  when  their  tails  are  pinched,  their  moving  jaws  (as 
in  mastication)  wdien  bitters  are  placed  in  their  mouths, 
and  their  raised  paivs  rubbing  their  noses,  wlien  irritating 
vapors  are  applied.  It  is  said  indeed  that  the  cries  are 
no  signs  of  pai^i ;  and  this  is  probable ;  but  they  are 
assuredly  signs  of  Sensibility. 

35.  The  frog  thus  mutilated  has  lost  indeed  all  its  spe- 
cial senses,,  except  Touch,  but  it  still  breathes,  struggles 
when  grasped,  thrusts  aside  the  pincers  which  irritate  it, 
or  wipes  away  acid  dropped  on  its  skin.  If  the  eye  be 
lightly  touched,  the  eyelid  closes  ;  if  the  touch  be  repeated 
three  or  four  times,  the  foreleg  is  raised  to  push  the  irri- 
tant away ;  if  still  repeated,  the  head  is  turned  aside  ;  but 
however  prolonged  the  irritation,  the  frog  neither  hops, 
nor  crawls  away,  as  he  does  wdien  the  cerebellum  remains. 
Place  the  brainless  frog  on  his  back,  and  if  the  medulla 
oblongata  remains  he  will  at  once  regain  the  normal  posi- 
tion ;  but  if  that  part  is  absent  he  will  lie  helpless  on  his 
back.     The  ]iower  of  preserving  equilibrium  in  difficult 


THE   NERVOUS   MECHANISM.  187 

positions  —  which  of  course  implies  a  nice  co-ordination 
of  muscles  —  resides  in  the  so-called  optic  lobes  of  the  frog 
(what  in  mammals  are  called  the  corpora  quadrigemina). 

37.  With  the  destruction  of  each  part  of  the  central 
mass  there  will  necessarily  be  some  disturbance  of  the 
mechanism ;  but  difficult  as  may  be  the  task  of  detecting 
by  experiment  what  is  the  normal  action  of  any  one  part, 
there  ought  to  be  no  hesitation  in  recognizing  the  persist- 
ence of  functions  after  certain  parts  are  destroyed.  The 
spinal  cord  is  anatomically  known  to  be  the  centre  from 
which  the  limbs,  trunk,  and  genito-urinary  organs  are 
innervated.  So  long  as  the  mechanism  of  the  actions  in- 
volving such  organs  is  intact,  no  removal  of  other  parts 
will  prevent  this  mechanism  from  exhibiting  its  normal 
action.  There  may  indeed  arise,  and  there  has  arisen,  the 
doubt  whether  Sensibility  is  involved  in  the  action  of 
any  nerve  centre  below  the  medulla  oblongata.  But  this 
doubt  is  founded  on  the  traditional  hypothesis  respecting 
the  seat  of  Sensation,  and  is  flagrantly  at  variance  with 
the  logical  conclusions  of  Anatomy  and  Experiment. 

38.  Anatomy  shows  that  the  structure  of  the  spinal 
cord  is  in  all  essential  characters  the  same  as  that  of  the 
medulla  oblongata ;  and  indeed  that  the  whole  central 
axis  has  one  continuous  tissue,  somewhat  variously  ar- 
ranged, and  in  relation  with  various  organs. 

Abundant  Experiment  has  shown  that  the  spinal  cord, 
apart  from  the  encephalon,  is  capable  of  acting  as  a  sen- 
sorial and  volitional  centre.  The  striking  facts  advanced 
by  Pfluger,  Auerbach,  and  myself,  have  not  been  im- 
pugned ;  *   but  their  interpretation  has   been   generally 

*  Pflugeu, Z>ie  Senso^'ischcii Fuiikf.ioiir.ndes Riic/cenmarks,lS53.  AuER- 
liACH,  Gilnzhurg's  Zcitschrift.  Jahrganf;  IV.  p.  486.  Lewes,  Leeda  Meet- 
I'nrj  of  British  Association,  18.58,  and  Physiolofjy  of  Common  Life,  1860. 

This  recognition  of  sensation,  and  even  of  volition,  in  spinal  actions 
may  be  foi;nd  in  the  writings  of  AViiytt,  Unzek,  Prochaska,  Legal- 


188  THE   PHYSICAL   BASIS   OF   MIND. 

rejected.  "VVe  showed  that  a  brainless  frog  responded  to 
stimulation  in  actions  which  bore  so  close  a  resemblance 
to  actions  admitted  to  be  sensorial  and  volitional  —  showed 
the  frog  ada]3ting  itself  to  new  conditions,  and  acquiriny 
dexterity  in  executing  actions  which  at  first  were  impos- 
sible or  difficult,  devisiyig  combinations  to  effect  a  purpose 
which  never  by  any  possibility  could  have  formed  part  of 
its  habits  —  manifesting,  in  a  word,  such  signs  of  Sensi- 
bility, that  no  one  witnessing  the  experiments  could  hesi- 
tate as  to  the  interpretation,  had  he  not  been  biassed  by 
the  traditions  of  the  schools. 

39.  Our  opponents  argued  that  in  spite  of  all  appearan- 
ces there  were  profound  differences  between  the  actions  of 
the  normal  and  the  brainless  animal,  and  that  the  latter  were 
due  simply  to  Reflex  Action.  I  also  insist  on  profound 
differences ;  but  underlying  these  there  are  fundamental 
identities.  As  to  the  Tieflex  Action,  two  points  will  here- 
after be  brought  forward:  1°,  that  «// central  action  is 
reflex,  the  cerebral  no  less  than  the  spinal ;  2°,  that  the 
hypotliesis  of  Eeflex  Action  being  purely  mccJtaniccd,  and 
distinguished  from  Voluntary  Action  in  not  involving  Sen- 
sibility, is  an  hypothesis  which  must  be  relinquished. 

40.  Postponing,  however,  all  discussion  of  these  points, 
let  me  here  say  that  the  doctrine  maintained  in  these 
pages  is  that  the  whole  cerebro-spinal  axis  is  a  centre  of 
Reflexion,  its  various  segments  taking  part  in  the  per- 
formance of  different  kinds  of  combined  action.  It  has 
one  common  property,  Sensibility ;  and  different  parts  of 
it  minister  to  different  functions  —  the  optic  centre  being 
different  from  the  auditory,  the  cerebral  from  the  spinal ; 
and  so  on.  To  make  this  intelligible,  however,  we  must 
first  learn  Avhat  is  known  respecting  the  properties  of 
nerve-tissue. 

LOIS,  and  Mayo  ;  but  the  establishment  of  the  Reflex  Theory  had  dis- 
placed it,  and  its  revival  dates  from  PflUger. 


THE  NERVOUS  MECHANISM.  189 


CHAPTEE    III. 

NEURILITY, 

41.  Observation  having  found  that  the  activity  of  a 
nerve  was  always  followed  by  a  sensation  when  the  nerve 
ended  in  a  centre,  and  by  a  movement  when  the  nerve 
ended  in  a  muscle,  Theory  was  called  upon  to  disclose  the 
nature  of  this  peculiar  property  of  nerves.  That  a  pecul- 
iar and  mysterious  power  did  act  in  the  nerves  no  one 
doubted ;  the  only  doubt  was  as  to  its  nature.  The  an- 
cient hypothesis  of  Animal  Spirits  seemed  all  that  was 
needed.  The  spirits  coursed  along  the  nerves,  and  obeyed 
the  mandates  of  the  Soul.  When  this  hypothesis  fell 
into  discredit,  its  place  was  successively  taken  by  the  hy- 
potheses of  Nervous  Fluid,  Electricity,  and  Nerve  Force. 
The  Fluid,  though  never  manifested  to  Sense,  was  firmly 
believed  in,  even  so  late  as  the  days  of  Cuvier ;  *  but 
when  the  so-called  electrical  currents  were  detected  in 
nerves,  and  the  nervous  phenomena  were  shown  to  resem- 
ble electrical  phenomena,  there  was  a  general  agreement 
in  adopting  the  electrical  hypothesis.  The  brain  tlien 
took  the  place  of  a  galvanic  battery;  the  nerves  were  its 
electrodes. 

42.  Closer  comparison  of  the  phenomena  detected  vari- 
ous irreconcilaljle  differences,  which,  if  they  proved  noth- 
ing else,  proved  that  nerve-action  took  place  under  con- 

*  Friedlandrr  {Versuch  ilber  die  innmi  Sinnn,  1826,  I.  77)  declares 
it  to  be  a  rational  necessity:  "  Die  Annalime  eines  Nervcnfluidums  ist 
Notliwendigkeit  der  Vernunft." 


190  THE  PHYSICAL  basis  of  mind, 

ilitions  so  special  as  to  demand  a  special  designation. 
Electricity  itself  is  so  little  understood,  that  until  its 
nature  is  more  precisely  known,  we  cannot  confidently 
say  more  than  that  nerve-action  resembles  electrical- 
action  ;  meanwhile  the  speciality  of  neural  conditions  ren- 
ders all  deduction  illusory  which  is  based  on  electrical- 
action  as  observed  under  other  conditions.  In  presence 
of  these  difficulties,  cautious  physiologists  content  them- 
selves with  assigning  the  observed  phenomena  to  the 
observed  and  inferred  conditions,  condensing  these  in  the 
convenient  symbol  "  nerve-force,"  without  pretending  to 
any  specification  of  the  nature  of  that  force.  It  may  be 
a  wave  of  molecular  movement  dependent  on  isometric 
change  or  on  metamorphic  change.  It  may  be  the  libera- 
tion of  molecular  tension  resembling  electricity ;  it  may  be 
electricity  itself.  But  whatever  the  nature  of  the  change, 
it  is  an  activity  of  the  tissue,  and  as  such  comes  under 
the  general  dynamic  conception  of  Force  or  Energy. 

43.  In  this  sense  the  term  has  nothing  equivocal  or 
obscure.  It  is  a  shorthand  expression  S3^mbolizing  cer- 
tain well-defined  observations.  Xevertheless,  it  is  a  term 
whicli  ^re  shall  do  well  to  avoid  when  possible,  and  to 
replace  by  another  having  less  danger  of  misinterpreta- 
tion ;  the  reason  being  that  Force  has  become  a  sort  of 
shibboleth,  and  a  will-o'-wisp  to  speculative  minds.  All 
that  we  knov-  of  Force  is  ]\Iotion.  But  this  is  too  meagre 
for  metempirical  thinkers,  who  disdain  the  familiar  expe- 
riences expressed  in  the  term  Motion,  and  demand  a  tran- 
scendent cause  "  to  account  "  for  what  is  observed.  They 
seek  an  entity  to  account  for  the  fact.  Motion  is  a  very 
definite  conception,  expressing  precise  experiences ;  we 
know  what  it  means,  and  know  that  the  laws  of  moving 
bodies  admit  of  the  nicest  calculation.  A  similar  pre- 
cision belongs  to  Force  when  understood  as  "mass  ac- 
celeration," or  M  V2.     But  this  does  not  content  those 


THE  NERVOUS  MECHANISM.  191 

metaphysicians  who  understand  by  Force  "  the  unknown 
reality  behind  the  phenomena"  —  the  cause  of  Motion. 
This  cause  they  refuse  to  recognize  in  some  antecedent 
motion  (what  I  liave  termed  a  "differential  pressure")/ 
but  demand  for  it  a  physical  or  metaphysical  agent :  the 
physical  agent  being  a  subtle  fluid  of  the  nature  of  Ether, 
or  a  nerve  atmosphere  surrounding  the  molecules ;  the 
metaphysical  agent  being  a  Spirit  or  aggregate  of  Soul- 
atoms.  The  second  alternative  we  may  decline  here  to 
discuss.  The  first  alternative  is  not  only  a  pure  fiction, 
but  one  which  is  inconsistent  with  the  demonstrable 
velocity  of  the  neural  process,  which  is  not  greater  than 
the  pace  of  a  greyhound,  whereas  the  velocities  of  light 
and  electricity  are  enormously  beyond  this.  It  is  incon- 
sistent also  with  the  observation  that  a  much  feebler  cur- 
rent of  electricity  is  requisite  for  the  stimulation  of  a 
muscle  through  its  nerve  than  when  directly  applied  to 
the  muscle :  a  proof  that  the  nerve  does  not  act  solely 
by  transmission  of  electricity —  unless  we  gratuitously  as- 
sume that  the  nerve  is  a  multiplicator. 

When  it  is  said  that  the  living  nerve  is  incessantly  lib- 
erating Force  which  can  be  communicated  to  other  tissues, 
the  statement  is  acceptable  only  if  we  reject  the  meta- 
])hysical  conceptions  it  will  too  generally  suggest  —  the 
conceptions  of  Force  as  an  entity,  and  of  its  being  passed 
from  one  object  to  another  like  an  arrow  shot  from  a  bow. 
The  physical  interpretation  simply  says  that  the  mole- 
cules of  the  nerve  are  incessantly  vibrating,  and  with 
varying  sweep ;  these  vibrations,  when  of  a  certain  en- 
ergy, will  set  going  vibrations  in  another  substance  by 
disturbing  the  tension  of  its  molecules,  as  the  vibrations 
of  heat  will  disturb  the  tension  of  the  gunpowder  mole- 
cules, and  set  them  sweeping  with  greater  energy :  this  is 
the  communication  of  the  force.  Just  as  we  say  that  a 
magnet  communicates  magnetic   force  to  a  bit  of  iron, 


192  THE  niYSiCAL  basis  of  mind. 

though  all  we  ineau  is  that  the  magnet  has  so  altered  the 
molecular  condition  of  the  iron  as  to  have  given  it  the 
movements  called  magnetism  —  in  short,  has  excited  in 
the  iron  the  dormant  property  of  becoming  magnetic  — 
so  we  say  the  nerve  communicates  its  force  to  the  muscle, 
exciting  in  the  muscle  its  dormant  property  of  contrac- 
tion. But  in  truth  nothing  has  passed  from  magnet  to 
iron,  or  from  nerve  to  muscle. 

44.  Do  what  we  will,  however,  there  is  always,  in  the 
present  condition  of  philosophical  chaos,  the  danger  of 
being  misunderstood  when  we  employ  the  term  Nerve- 
force  ;  and  I  have  proposed  the  term  Neurility  as  an 
escape  from  the  misleading  suggestions.  It  is  a  symbol 
expressing  the  general  property  of  nerve-tissue.  For  rea- 
sons presently  to  be  stated,  I  restrict  Xeurility  to  the 
peripheral  system,  employing  Sensibility  for  the  central 
system.  The  excited  muscle  manifests  its  special  prop- 
erty of  Contractility ;  the  excited  nerve  manifests  its 
special  property  of  Neurility;  the  excited  centre  mani- 
fests its  special  property  of  Sensibility.*     The  terms  are 

*  These  terms  and  the  conception  they  embody  were  proposed  by  me 
in  1859  in  a  paper  "  On  the  necessity  of  a  reform  in  Xerve-physiology," 
read  at  the  Aberdeen  meeting  of  the  British  Association,  and  were  repro- 
duced in  the  Physiology  of  Common  Life.  (Prof.  Owen,  probably  in 
forgetfulness  of  my  suggestion,  proposed  "neuricity."  Lectures  on  the 
Comi).  Anat.  of  Vertebrates,  1866,  I.  p.  318.;  The  terms  were  fortunate 
enough  to  meet  with  acceptance  from  some  physiologists  both  in  England 
and  France  ;  and  the  conception  has  been  more  widely  accepted  than 
the  terms.  The  most  distinguished  approver  was  Prof.  Vulpian. 
"  Faute  d'une  meilleure  determination  on  pent,  avec  M.  Lewes,  donner 
a  la  propriete  physiologique  des  fibres  nerveuses  le  nom  de  neurilite; 
c'est  la  ce  qui  correspondra  a  la  contractilite  des  fibres  musculaires." 
Lerfins  sur  la  physiologic  dii  systeme  nerveux,  1866,  p.  220.  He  also 
adopted  my  suggestion  (since  modified)  of  Sensibility  as  the  property  of 
ganglionic  cells.  Compare  also  Gav arret,  PMnomenes  physiques  de  la 
Vie,  1869,  pp.  213  and  222.  Taule,  Notions  sur  la  nature  de  la  matiere 
organisee,  1866,  p.  131.  Charles  PiOBIX,  Anatomie  et  physiologie  ccl- 
lulaires,  1873,  p.  166. 

By  these  channels,  and  by  the  German,  Italian,  Russian,  Polish,  and 


THE  NERVOUS  MECHANISM.  193 

•simply  descriptive,  and  cany  with  them  no  hypothesis  as 
to  lohat  Neurility  is  in  its  hidden  process,  nor  hoio  Sensi- 
bility arises  in  a  nerve-centre,  and  not  elsewhere.  We 
know  that  a  stimulated  muscle  contracts,  and  we  express 
the  fact  by  assigning  to  muscular  tissue  the  property  of 
Contractility.  We  know  that  a  stimulated  nerve  trans- 
lates an  impulse  from  one  point  to  another,  and  excites 
the  muscle  to  contract ;  and  we  express  the  fact  by  as- 
signing to  nerve-tissue  the  property  of  transmitting  stim- 
ulation, which  is  further  specified,  as  unlike  other  trans- 
missions, by  the  term  Neurility. 

45.  What  is  the  meaning  attached  to  the  term  Prop- 
erty, and  how  it  is  distingui,shed  from  Function,  has  been 
already  expounded  in  Problem  1,  §§81-6.  There  also 
was  laid  down  the  principle  of  identity  of  structure  imjjly- 
ing  identity  of  property.  Inasmuch  as  observation  reveals 
a  fundamental  similarity  in  the  structure  of  the  nervous 
tissue  throughout  the  animal  kingdom,  we  must  conclude 
the  existence  of  a  fundamental  similarity  in  the  property 
of  that  tissue :  a  conclusion  confirmed  by  observation. 
There  is  a  corresponding  agreement  in  the  organs  and 
functions  ;  so  that,  within  certain  limits,  the  experiments 
performed  on  an  insect  may  be  verified  on  a  mammal. 
Everywhere  nerve-tissue  has  certain  characters  in  com- 
mon, accompanied  by  variations  in  the  degree  and  mode 
of  manifestation  corresponding  with  variations  in  struc- 
ture and  connection.  Obvious  as  the  fact  is,  we  must 
emphasize  the  great  variety  which  accompanies  the  un- 
derlying uniformity,  for  this  is  recognizable  both  in  the 
individual  organism  and  in  the  animal  kingdom  at  large. 

Hungarian  translations  of  my  woik,  the  suggostions  were  carried  over 
Europe,  crept  into  scientific  journals,  and  became  known  to  writers  who 
never  heard  of  me.  I  only  mention  thi^se  facts  lest  the  reader  should 
suppose  that  my  views  had  been  anticipated  by  certain  continental 
writers. 

VOL.  III.  9  M 


194  THE   niYSICAL   BASIS   OF   MIND. 

Even  such  seemingly  individual  terms  as  nerve-cell  and 
nerve-fibre  are  in  truth  generic;  and  the  description  which 
accurately  represents  one  cell  or  fibre  needs  modifying  for 
others. 

Properties  are  generalized  expressions;  they  result  from 
the  comjyodtion,  the  structure,  and  the  tcj:turc  of  a  sub- 
stance. Thus  one  bar  of  iron  may  differ  from  another  of 
equal  bulk  in  being  more  or  less  crystalline  in  structure, 
though  having  the  same  composition  and  the  same  tex- 
ture. This  difference  will  modify  the  mode  of  manifes- 
tation of  the  iron-properties.  Cast-iron  pillars,  for  ex- 
ample, will  support,  as  a  roof,  a  weight  which  would 
break  them  if  suspended ;  wrought-iron  pillars  of  similar 
bulk  will  bear  a  weight  suspended  which  would  crush 
them  as  a  roof.  Yet  both  cast  and  wrought  iron  pillars 
have  the  same  properties,  because  they  have  the  same 
composition  and  similar  structure ;  the  variation  of  struc- 
ture only  producing  a  difference  in  the  modes.  Texture 
may  also  vary.  The  bar  of  iron  may  be  beaten  into  a 
plate,  rolled  into  a  cylinder,  or  split  into  wire-work,  with- 
out any  change  in  its  properties,  but  with  marked  dif- 
ferences in  its  modes  of  manifestation,  and  in  the  uses 
to  wdiicli  it  may  be  applied.  These  uses  are  of  course 
dependent  on  the  connections  established  betw^een  the 
iron  and  other  things.  In  Physiology,  uses  are  called 
functions. 

46.  Nerve-tissue  must  be  understood  as  having  ever}-- 
where  the  same  general  Property.  In  one  animal  and  in 
another,  in  one  part  and  in  another,  jSTeurility  is  the  same 
in  kind,  but  not  everywhere  manifesting  the  same  degree, 
nor  applied  to  the  same  Function.  The  conqjosition  of 
nerve-tissue  varies,  but  not  more  than  the  composition  of 
all  other  organized  substances ;  the  stnicturc  is  variable, 
but  only  within  a  small  range  ;  the  texture  also  ;  while  the 
connections  are  very  various.     Hence,  whatever  the  varia- 


THE  NERVOUS  MECHANISM.  195 

tions  in  composition  or  structure,  the  nerve-fibre  has  every- 
where one  fundamental  property,  which  in  connection  with 
a  muscle  has  the  functional  activity  of  exciting  contrac- 
tion ;  in  connection  with  a  gland  of  exciting  secretion ; 
and  in  connection  with  a  centre  of  exciting  reflexion.* 

47.  Had  a  clear  idea  of  Function  as  dependent  on  con- 
nexion been  present  to  their  minds  certain  physiologists 
would  hardly  have  raised  the  mirage  of  "  Nerve-force,"  a 
mysterious  entity  endowed  with  "  specific  energies,"  and 
capable  of  producing  vital  and  psychical  phenomena  by 
an  occult  process ;  nor  would  others  have  been  led  to  the 
monstrous  hypothesis  of  particular  nerve-cells  being  en- 
dowed with  thought,  instinct,  and  volition.  They  would 
have  sought  an  explanation  of  functions  in  the  combined 
properties  of  the  co-operant  organs  and  tissues.  They 
would  not  have  endowed  one  nerve  with  Sensibility,  and 
another  nerve  of  identical  structure  with  Motility  ;  f  one 
nerve  with  a  motor  property,  and  another  with  the  oppo- 
site property  of  inhibition.  They  would  have  seen  that 
all  nerves  have  the  same  property,  but  different  uses  when 
in  different  connexions. 

48.  Throughout  the  animal  kingdom  we  see  movement 
following  on  stimulation.  Stimulation  may  be  defined 
the  cliange  of  molecular  equilibrium.  The  stimulation 
of  a  muscle  is  produced  indirectly  tln^ougli  a  change  in 

*  "  La  force  nerveuse  n'existe  pas  comme  puissance  independant  des 
proprietos  de  tissu.  Elle  consiste  en  Taction  des  parties  excites,  sur  les 
parties  excitables,  I'etat  de  I'excitation  des  premieres  agissant  comme 
impression  ou  stimulation  sur  les  secondes."— Landuy,  Traite  des  Pa- 
rahjsics,  1859,  I.  142. 

t  "  Le  systeme  nerveux  est  tout  h,  la  fois  I'origine  des  sensations  ct 
I'origine  des  mouvements.  Mais  est-ce  par  une  propriete  unique,  ou 
par  deux  jiroprii'tes  divcrses  qu'il  determine  deux  phenomenes  aussi  dis- 
tincts  ?"  Floi'I'.kxs,  Rccherchcs  sur  leu  proprietis  ct  les  fonct.ions  du  Sys- 
Ume  Axrveax,  1824,  p.  1.  He  concludes  tliat  "la  puissance  nerveuse 
n'est  pas  unitiue  ;  il  n'y  a  pas  une  seule  propriete,  il  y  en  a  deux,"  p.  24. 
In  this  he  has  been  generally  followed. 


196  THE   niYSICAL   BASIS   OF   MIND. 

the  nerve,  ov  directly  through  a  change  in  the  muscle 
itself.  In  the  simplest  organisms  there  is  no  trace  of 
nerve-tissue ;  hut  their  substance  manifests  Irritability 
(or  as  it  is  often  called  Sensibility) ;  and  a  stimulus  to 
one  part  is  propagated  throughout  —  the  whole  body 
moves  \\'hen  touched.  Even  in  Polypes,  where  there  is 
the  beginning  of  a  differentiation,  the  motion  is  slowly 
propagated  from  one  part  to  the  rest.  A  single  tentacle 
retracts  when  touched ;  but  the  movement  rarely  ends 
there ;  it  is  slowly  communicated  from  one  tentacle  to 
the  other,  and  from  them  to  the  whole  mass.  Touching 
the  body,  however,  will  not,  if  the  touch  be  slight,  cause 
the  tentacles  to  move ;  so  that  we  see  here  a  beginning 
of  that  principle  of  specialization  which  is  so  manifest  in 
the  higher  organisms :  the  tentacles  have  become  the 
specially  sensitive  parts.  Ascending  higher  in  the  scale 
of  organisms  we  find  those  which  habitually  move  par- 
ticular parts  without  at  the  same  time  necessarily  moving 
the  rest ;  and  this  independence  of  parts,  accompanying 
a  more  perfect  consensus,  we  find  to  be  developed  |:)ari 
passu  with  a  nervous  system.  An  immense  variety  of 
part-movements,  with  varying  combinations  of  such  move- 
ments, is  the  physiological  expression  of  the  more  com- 
plex nervous  system. 

48  a.  Deferring  what  has  to  be  said  of  Sensibility  till 
the  next  chapter,  we  may  here  touch  on  its  relation  to 
Irritability,  which  is  often  iised  as  its  synonym.  Ohjec- 
tively  it  cannot  be  distinguished  from  Irritability,  nor 
indeed  from  the  most  general  phenomenon  of  reaction 
under  stimulation  ;  in  this  it  is  an  universal  property. 
But  subjectively  it  is  distinguishable  as  a  peculiar  mode 
of  reaction,  only  known  in  nerve-tissues.  While  all  tis- 
sues are  irritable,  and  react  on  being  stimulated,  each  tis- 
sue has  its  special  mode  of  reaction.  The  secreting-cell 
reacts  differently  from  the  muscle-cell.     The  reaction  of 


THE  NERVOUS  MECHANISM.  197 

the  nerve  is  the  innervation  of  a  centre  or  a  muscle ; 
the  reaction  of  an  innervated  centre  is  sensation ;  of  a 
muscle,  contraction.  There  are  three  aspects  of  neural 
reaction :  excitation,  propagation  of  the  disturbance,  and 
innervation.  The  first  is  expressed  by  irritability,  the 
second  by  conductibility,  the  third  by  sensibility ;  but 
these  are  only  artificial  distinctions  in  the  general  phe- 
nomenon of  transmitted  excitation.  The  nerve  substance 
is  specially  distinguished  by  its  instability  of  molecular 
equilibrium ;  it  imdergoes  chemical  change  with  a  readi- 
ness comparable  to  that  of  explosive  substances.  Hence 
its  facility  of  propagation  of  disturbance.  There  is  irri- 
tability and  propagation  of  disturbance  in  muscular  tis- 
sue, notably  evideiit  in  the  continuous  tissue  of  the  heart, 
intestines,  and  ureter;  but  the  propagation  is  slow  and 
diffusive ;  whereas  in  the  nerve  it  is  rapid,  and  restricted 
along  a  definite  path.  By  this  rapidity  and  restriction 
the  force  of  the  impact  is  increased ;  and  thus  a  slight 
stimulus  applied  to  the  nerve  is  capable  of  disturbing  the 
state  of  the  muscle. 

49.  Thus  while  molecular  movement  is  a  fundamental 
condition  of  Vitality,  and  is  incessant  throughout  organ- 
ized substance,  the  massive  movements  of  the  organism, 
and  the  movements  of  particular  parts,  are  the  directed 
quantities  of  this  molecular  agitation.  They  are  due  to 
stimulation.  AVe  distinguish  this  from  mechanical  im- 
pulsion. It  is  a  vital  process  involving  molecular  change; 
it  is  not  simply  the  communication  of  motion  from  with- 
out, but  the  excitation  of  motion  within.  It  is  not  like 
the  blow  which  merely  displaces  an  object,  but  like  the 
blow  which  disturbs  its  molecular  equilibrium.  The  ef- 
fect, therefore,  depends  on  this  molecular  condition  :  the 
l»low  which  scatters  a  heap  of  gunpowder  will  explode  a 
fulminating  salt,  and  this,  in  exploding,  will  excite  the 
gunpowder  to  explode.     Tiic  stimulus  which  is  too  leoblc 


198  THE  niYsiCAL  basis  of  mind. 

to  excite  contraction  in  a  muscle  will  be  powerful  enough 
to  excite  the  neurility  of  a  nerve,  and  that  will  excite  the 
contractility  of  the  muscle.  The  nerve-force  is  simply- 
neural  stimulus.  It  acts  upon  the  other  tissues  as  the 
nitrogenous  salt  upon  the  gunpowder. 

Although  it  is  now  common  to  speak  of  nerves  as  trans- 
mitting waves  of  molecular  motion,  and  to  regard  nerves 
as  the  passive  medium  for  the  "  transference  of  force," 
whereby  the  force  is  thus  made  an  abstract  entity,  we 
must  always  remember  that  such  phrases  are  metaphors, 
and  that  the  truer  expression  will  be  not  "transference  of 
force,"  but  the  "  propagation  of  excitation."  I  mean  that 
it  is  not  the  force,  of  the  impact  nor  its  energy  wliich  a 
nerve  transmits,  it  is  the  vibratory  change  produced  in  the 
nerve  by  the  impact,  which  excites  another  change  in  the 
organ  to  which  the  nerve  goes.  We  know  by  accurate 
measurements  that  the  excitation  of  a  nerve  lasts  nmcli 
longer  than  the  stimulus,  a  momentary  impact  producing 
an  enduring  agitation.  We  know  also  that  tlie  excitation 
of  a  centre  lasts  longer  than  the  muscular  contraction  it 
has  initiated.  We  know,  moreover,  that  a  nerve  may  be 
totally  incapable  of  conducting  an  external  stimulus,  yet 
quite  capable  of  conducting  a  central  stimulus ;  were  it 
a  passive  conductor  like  a  wire  this  would  not  be  so.* 

50.  The  nerve  is  essentially  an  exciter  of  change,  and 
thereby  a  regulator.  A  muscle  in  action  does  not  appre- 
ciably determine  action  in  any  other  (except  in  the  com- 
paratively rare  cases  of  anastomosing  muscles) ;  a  secret- 
ing cell  does  not  propagate  its  excitation  to  others.  The 
nerve,  on  the  contrary,  not  only  propagates  its  excitation, 

*  "I  have  raised  and  stretched  the  thick  orbital  nerve  of  horses  on 
the  handle  of  a  scalpel,  like  a  string  on  the  bridge  of  a  violin,  without 
exciting  the  least  sensation  ;  but  as  soon  as  mechani>jal  or  chemical  irri- 
tation had  given  rise  to  inflammation  of  the  nerve  a  gentle  touch  caused 
violent  pain."  —  Romberg,  Nervous  Diseases  (translated  for  the  Syden- 
ham Society),  I.  10. 


THE  NERVOUS  MECHANISM.  199 

and  awakens  the  activity  of  the  muscle  or  gland  with 
which  it  is  connected,  but  through  the  centre  affects  the 
whole  organism  — 

"Ein  Selling  tausend  Verbindungen  schlagt." 

Thus  it  is  that  stimulation  which  in  the  simpler  organ- 
isms was  diffused  throughout  the  protoplasm,  has  in  the 
complex  organisms  become  the  specialized  property  of  a 
particular  tissue. 

51.  Two  general  facts  of  supreme  importance  must 
now  be  stated :  One  is  the  law  of  stimulation  —  every 
excitation  pursues  the  jxith  of  least  resistance.  The  second 
is  the  condition  of  stimulation  —  unlike  tnechanical  im- 
indsion,  it  acts  only  at  insensible  distances. 

52.  This  means  that  although  a  nerve  may  be  excited 
by  any  stimulus  external  to  it  which  changes  its  molecu- 
lar condition,  no  propagation  of  that  change  (i.  e.  no  stinm- 
lation  througli  the  nerve)  is  possible  except  through  con- 
tinuity of  substance.  Mere  physical  contact  suffices  to 
excite  the  nerve ;  but  if  there  be  an  interruption  of  con- 
tinuity in  the  nerve  itself,  no  stimulus-wave  passes  across 
that  line.  Cut  a  nerve,  and  bring  the  divided  surfaces 
once  more  into  close  contact,  there  will  still  be  such  a 
solution  of  continuity  as  to  arrest  the  stimulus-wave, 
mere  physical  contact  not  sufficing  for  the  propagation. 
Whereas  across  the  cut  ends  of  a  divided  nerve,  even 
visibly  separated,  the  electric  current  easily  passes.  T]iis 
necessity  for  the  vital  continuity  of  tissue  in  the  propaga- 
tion of  stimulation  must  always  be  borne  in  mind.  The 
presence  of  a  membrane,  liowever  delicate,  or  of  any  tissue 
liaving  a  different  molecular  constitution,  suffices  to  arrest 
or  divert  the  wave.  I  conceive,  therefore,  that  it  is  abso- 
lutely indispensable  that  a  nerve  should  terminate  in  and 
hlend  with  a  muscle  or  a  centre,  otherwise  no  stimulation 
of  muscle  or  centre  will  take;  place  through  tlic  nerve. 


200 


THE   niYSICAL   BASIS   OF   MIND. 


53.  The  difierence  between  excitation  from  contact  and 
stimulation  from  continuity  may  be  thus  illustrated.  In 
Fig.  13  we  see  the  legs  of  a  frog  attached  to  the  spine  by 


Fig.  13 


the  lumbar  nerves  (J),  and  lying  on  the  muscles  (m)  of 
one  leg  is  the  nerve  (c)  of  another  frog's  leg.  Applying 
the  electrodes  to  (l),  the  muscles  (m)  are  violently  con- 
tracted ;  not  only  so,  but  their  contraction  excites  the 
other  nerve  (c),  and  the  leg  attached  to  this  nerve  is 
thereby  thrown  into  contraction.  This  "secondary  con- 
traction," as  Dubois  Reymond  calls  it,  might  be  supposed 
to  be  due  to  a  diffusion  of  the  electrical  current ;  but  that 
it  is  due  to  a  change  in  the  muscles  (m)  is  proved  by  deli- 
cate experiments  showing  that  the  movements  in  tlie 
detached  leg  are  of  precisely  the  same  kind  as  those  in 
the  legs  directly  stimulated.  If  there  is  only  a  muscular 
shock  in  the  one  case,  there  is  only  a  muscular  shock  in 
the  other ;  if  tliere  is  tetanus  in  the  one,  there  is  tetanus 


THE  NEEVOUS  MECHANISM.  201 

in  the  other ;  if  the  muscles  of  the  first  leg  are  fatigued 
and  respond  slowly  and  feebly,  the  response  of  the  second 
is  slow  and  feeble.  Moreover,  the  secondary  contraction 
may  be  produced  by  chemical  or  mechanical  stimulus,  as 
well  as  by  the  electrical. 

54.  Although  tlie  contraction  of  a  muscle  is  thus  seen 
to  be  capable  of  exciting  a  nerve  in  contact  with  it,  the 
reverse  is  not  true :  we  can  produce  no  contraction  in 
a  muscle  by  exciting  a  nerve  simply  in  contact  with 
the  muscle,  and  not  penetrating  its  tissue  and  termi- 
nating there.  Accordingly  we  always  find  a  nerve  when 
about  to  enter  a  muscle  or  a  centre  losing  its  protecting 
envelopes  ;  it  gradually  becomes  identified  as  a  proto- 
plasmic thread  witli  the  protoplasm  of  the  muscle  or  the 
centre. 

55.  Neurility,  then,  is  the  propagation  of  molecular 
change.  Two  offices  are  subserved  by  the  nervous  sys- 
tem, which  may  respectively  be  called  Excitation  —  the 
disturbance  of  molecular  tension  in  tissues,  and  conse- 
quent liberation  of  their  energies  ;  and  Co-ordination  — 
the  direction  of  these  several  energies  into  combined 
actions.  Thus,  when  the  muscle  is  in  a  given  state  of 
molecular  tension,  the  stimulation  of  its  nerve  will  change 
that  state,  causing  it  to  contract  if  it  be  in  repose.  But 
this  stimulation,  which  will  thus  cause  a  contraction,  will 
be  arrested,  if  at  the  same  time  a  more  powerful  stimula- 
tion reaches  the  antagonist  muscle,  or  some  distant  cen- 
tre :  then  the  muscle  only  tends  to  contract. 

ORIGIN   OF  NERVE-FORCE. 

56.  After  this  brief  account  of  Neurility  we  may  pass 
to  the  consideration  of  its  origin.  Arc  we  to  understand 
that  this  property  belongs  to  the  nerves  themselves  in  the 
sense  in  which  Contractility  belongs  to  the  muscles  ?  or 
are  we  to  accept  tlie  teaching  which  assigns  the  origin  of 


202  TIIE   niYSICAL   BASIS   OF   MIND. 

"nerve-force"  to  the  ganglia,  and  regards  the  nerves  sim- 
ply as  passive  conductors  of  a  force  developed  in  the 
cells  ? 

57.  It  is  now  many  years  since  I  ventured  to  criticise 
the  reigning  doctrine,  and  to  urge  the  necessity  of  consist- 
ently carrying  out  the  distinction  between  Property  and 
Function.  I  called  attention  to  the  positive  evidence 
which  contradicted  the  idea  of  passive  conduction ;  and 
pointed  out  the  illusory  nature  of  the  favorite  analogy,  in 
which  ganglia  were  likened  to  batteries,  and  nerves  to 
the  conducting  wires.  But  the  old  image  still  exerts  its 
empire ;  and  writers  are  still  found  speaking  of  the  brain 
as  a  telegraphic  bureau,  the  ganglia  as  stations,  and  the 
nerves  as  wires.  In  the  cells  of  the  gray  substance  they 
place  a  constantly  renewing  reservoir  of  nerve- force. 
There  the  force  is  elaborated,  stored  up,  and  from  thence 
directed  along  the  nerves.  The  sensory  nerve  "  transmits 
an  impression  to  the  brain "  —  as  the  wire  transmits  a 
message  to  tlie  bureau.  The  motor  nerve,  in  turn, 
'•'transmits  the  mandates  of  the  will" — and  all  is  clear! 
Clear,  until  we  come  to  translate  metaphors  into  visible 
facts,  or  try  to  conjure  up  some  mental  image  of  the 
process.  For  myself,  I  can  only  conceive  nerve-force  as 
the  activity  of  the  nerve,  and  not  of  something  else.  This 
becomes  still  more  evident  when  J  find  that  the  activity 
is  equally  manifest  after  its  imaginary  source  has  been 
removed.  Transmitting  impressions,  or  messages,  implies 
as  a  preliminary  that  there  should  be  an  impressible 
agent,  or  a  message-sender,  at  the  periphery.  Xo  one  sup- 
poses that  simply  touching  one  end  of  a  wire  would  send 
an  "impression"  or  a  "message"  to  the  battery;  or  that 
without  the  battery  this  touch  would  evolve  a  current. 
The  battery  is  indispensable ;  in  it  is  evolved  the  current 
which  the  wire  transmits.  Not  so  the  ganglion,  or  brain. 
Remove  the  wire  from  its  connection  with  the  battery, 


THE  NERVOUS  MECHANISM.  203 

and  it  is  a  bit  of  wire,  nothing  more.  But  remove  a 
nerve  from  its  connection  witli  a  ganglion,  and  it  is  still 
active  as  nerve,  still  displays  its  ^Neiirility  when  excited, 
still  moves  the  muscle  as  before.  The  amputated  limb 
will  move  when  its  nerves  are  stimulated,  just  as  when 
a  reflex  from  its  centre  moved  it.  Every  one  knew  the 
fact ;  it  was  staring  them  in  the  face,  yet  they  disregarded 
it.  Even  the  old  anatomist,  Willis,  had  recorded  experi- 
ments which  ought  to  have  opened  their  eyes.  He  tied 
the  phrenic  nerve,  and  found  that,  when  he  irritated  it 
below  the  ligature,  the  diaphragm  moved ;  but  when  he 
irritated  it  above  the  ligature,  no  movement  followed. 
Since  his  days,  thousands  of  experiments  have  shown  that 
the  presence  of  a  ganglion  is  not  necessary  to  the  action 
of  a  nerve.* 

58.  Of  course  an  explanation  was  ready.  The  nerve 
was  said  to  have  been  "  endowed  with  force "  from  its 
ganglion  during  their  vital  connection;  and  this  force, 
stored  up  in  the  nerve,  was  disj)Osable  for  some  time  after 
separation  from  the  ganglion.  We  need  not  pause  to 
criticise  this  misty  conception  of  one  part  "  endowing  " 
another  with  force ;  the  plain  facts  afford  the  best  answer. 
There  seemed,  indeed,  a  confirmation  of  the  hypothesis  in 
the  fact  that  although  the  nerve  separated  from  its  gan- 
glion was  capable  of  excitation,  yet  after  a  few  excitations 
it  was  exhausted,  and  ceased  to  stimulate  the  muscle.  It 
seemed  like  the  piece  of  magnetized  iron  which  would  act 
as  a  temporary  magnet,  though  quickly  losing  this  bor- 
rowed power.  But  the  whole  fabric  fell  —  or  ought  to 
have  fallen  —  when  extended  observation  discovered  that 

*  The  cxperimeiits  of  IIaller,  Sar  la  nature  sensiUc  ct  irritable  des 
}>a,rtics,  I.  24r);  and  the  remarks  of  Prochaska,  De  Functionihus  Syste- 
matis  Ncrvosi  (translated  by  Laycock  in  the  volume  publislied  by  the 
Sydenliam  Society,  p.  396),  ought  to  have  sufficed.  See  further  on, 
Chap.  V. 


204  THE  niYsic.vL  basis  of  mind. 

this  exhausted  nerve  would,  if  left  in  repose,  recover  its 
lost  power.  A  nerve  preserves  its  e.xcitability  as  long  as 
it  preserves  its  structural  integrity,  and  recovers  its  power 
in  recovering  that  integrity.  The  lengtli  of  time  varies.* 
Gratiolet  found  the  muscles  in  the  leg  of  a  tortoise,  which 
had  been  amputated  a  week  before,  contract  when  the 
nerves  were  irritated ;  and  Schiff  found  the  divided  nerve 
of  a  winter  frog  excitable  at  the  end  of  three  weeks. 
Even  after  all  excitability  has  disappeared,  it  will  reap- 
pear if  arterial  blood  be  injected ;  just  as  muscles  whicli 
have  already  begun  to  assume  cadaveric  rigidity  recover 
their  contractility  after  transfusion.  Nor  is  this  all.  The 
separated  nerve  finally  degenerates,  and  loses  all  its  struc- 
tural characters  and  physiological  properties ;  yet  under 
favorable  conditions  it  will  regenerate — recover  its  struc- 
tures and  properties ;  and  this  even  apart  from  a  centre, 
as  Vulpian  showed.  Very  noticeable  is  the  fact  that  the 
force  said  to  be  produced  in  the  centre,  and  only  "  con- 
veyed "  by  the  nerve,  vanishes  gradually  from  the  centre 
to  the  periphery,  and  recovers  from  the  periphery  to  the 
centre  —  the  part  of  the  nerve  whicli  is  farthest  from  the 
centre  being  excitable  when  the  part  nearest  the  centre  is 
still  inexcitable.  Again,  when  a  nerve  is  pinched,  con- 
traction in  tlie  muscle  follows ;  but  the  pinch  has  for  a 
time  so  disturbed  the  structural  integrity  of  the  nerve  (at 
that  spot)  that  no  irritant  applied  to  the  spot,  or  hetiveen 
it  and  the  centre,  will  be  followed  by  contraction,  whereas 
helow  the  spot  an  irritation  takes  effect.  This  is  another 
form  of  the  experiment  of  Willis.  Even  in  its  normal 
state,  the  nerve  has  different  degrees  of  excitability  in 
different  parts  of  its  course,  —  a  fact  discovered  by 
rfliiger  which  is  quite  irreconcilable  with  the  hypothe- 
sis of  passive  conduction.     Doubts  have  been  thrown  on 

*  In  mammals  about  three  days,  in  birds  four  da3's,  in  frogs  fourteen 
to  twenty  days. 


THE  NERVOUS  MECHANISM.  205 

Pfliiger's  interpretation,*  namely,  that  there  is  an  ava- 
lanche-like accumulation  of  energy  proportionate  to  the 
length  of  the  stimulated  portion ;  but  the  fact  remains, 
that  one  and  the  same  irritant  applied  successively  to  two 
different  points  of  a  nerve  does  not  irritate  the  muscle  in 
the  same  degree.  Llunk  also  finds  the  velocity  of  trans- 
mission in  a  motor  nerve  increases  as  it  approaches  its 
termination  in  the  muscle.*!* 

59.  Nothing  can  be  more  unlike  the  conduction  of  an 
electric  current  than  this  excitation  of  Neurility ;  nothing 
more  accordant  with  the  idea  of  it  as  a  vital  property  of 
the  tissue.  The  notion  of  its  being  derived  from  a  centre 
is  on  a  par  with  the  notion  first  successfully  combated  by 
Haller,|  that  the  muscle  derived  its  Contractility  from 
the  nerves ;  or  the  analogous  notion  that  the  electric 
organ  in  fishes  derived  its  property  from  the  brain.  In- 
deed, it  was  in  support  of  the  hypothesis  that  the  brain 
was  a  battery,  and  nerves  the  conductors,  that  the  phe- 
nomena observed  in  electrical  fishes  were  frequently  cited. 
The  electric  organ  was  seen  to  be  connected  with  the 
brain ;  its  discharges  were  under  the  control  of  the  ani- 
mal, and  were  destroyed  on  one  side  when  the  brain  on 
the  corresponding  side  was  destroyed.  But  Charles  Eobin 
long  ago  suggested,  what  indeed  ought  never  to  have  been 
doubted,  that  the  brain  was  not  the  source  of  the  elec- 
tricity ;  but  that  the  tissue  of  the  electric  organ  itself  had 
this  special  property,  which  the  nerve  merely  called  into 
activity.  The  suggestion  has  been  experimentally  veri- 
fied by  M.  Moreau,  who  divided  all  the  nerves  supplying 
the  electric  organ  on  one  side,  and,  liaving  thus  cut  off  all 

*  Ruth r.i; FORD,  in  Journal  of  Anatomy,  1873,  No.  VIII.  p.  331. 
(Fleischl  denies  that  the  nerve  in  situ  lias  difTerent  degrees  of  reaction. 
Sitzunr/sherichle  (ler  Wiener  Akad.,  December,  1876.) 

+  MuNK,  in  the  Archiv  fur  AnaL,  1860,  p,  798. 

t  Halleii,  3f6moires  sur  la  nature  sensible  ct  irritable  des  parties. 


206  THE  niYsiCAL  basis  of  mind. 

communication  -with  the  brain,  produced  electrical  dis- 
charges by  irritating  the  nerves  ;  precisely  as  the  muscles 
are  made  to  contract  when  the  divided  nerves  are  irri- 
tated. Had  tlie  experiment  ceased  here,  it  might  have 
been  interpreted  on  the  old  hypothesis :  tlie  electric 
organ  might  be  supposed  to  liave  a  certain  amount  of 
electric  force  condensed  in  it,  stored  up  there,  as  it  is  said 
to  be  in  the  nerves,  and  discharged  when  tlie  organ  is  irri- 
tated. But  experiment  has  decided  this  point  also.  Elec- 
tric fishes  notoriously  exhaust  their  power  by  a  few  dis- 
charges, and  recover  it  after  repose.  When  ]\L  IMoreau 
had  exhausted  his  mutilated  fishes,  he  replaced  them  in 
the  water,  and  allowed  them  repose.  On  again  irritating 
the  divided  nerves,  the  discharges  were  again  produced.* 

60.  On  all  sides  the  idea  of  nerves  deriving  their  power 
from  another  source  than  their  own  substance  is  seen  to 
be  untenable.  A  j^nori  this  might  have  been  concluded. 
Neurility  is  the  vital  property  of  nerve-tissue.  "  Nerve- 
force"  is  nerve-action  —  molecular  changes  in  the  nerve 
itself,  not  in  some  remote  substance.  That  nerve  and 
centre  are  vitally  connected  is  true ;  and  what  their  phys- 
iological relations  are  will  hereafter  be  examined ;  but 
we  must  dismiss  the  idea  of  nerves  having  the  relation  to 
centres  that  electrodes  have  to  batteries. 

61.  In  proposing  the  term  Xeurility,  I  not  only  wi.shed 
to  get  rid  of  the  ambiguities  which  hovered  round  "  nerve- 
force  "  and  "  nerve-current,"  but  to  recall  the  physiologi- 
cal principle  that  properties  are  dependent  on  structures ; 
and  therefore  that  the  special  property  of  nerve-tissue  is 
conditioned  by  its  structure.  Neurility  is,  of  course,  an 
abstraction  ;  but  so  is  the  nerve  an  abstraction.  The  con- 
crete manifestations  are  the  several  nerve-actions.  These 
we  classify  and  specify.  One  class  we  call  sensory, 
another  class  motor ;  not  because  the  nerve-action  itself 

»  Com2)tes  Rcndus,  1862,  LIV.  p.  965. 


THE  NERVOUS  MECHANISM.  207 

is  different,  but  because  it  is  in  each  class  in  a  different 
functional  relation  to  other  parts.  In  classing  men  as 
governors  and  governed,  employers  and  employed,  we  do 
not  suppose  antliropological  distinctions,  but  only  differ- 
ences in  their  social  functions. 

62.  This  is  the  modification  of  the  Law  of  Bell  to 
which  reference  was  made  in  §  26.  It  replaces  the  idea 
of  two  different  kinds  of  nerve,  sensory  and  motor,  by 
that  of  two  different  anatoniical  connections.  I  need  not 
reproduce  here  the  argument  with  which  I  formerly  criti- 
cised the  supposed  distinction  between  sensory  and  motor 
nerves ;  because  the  old  idea  is  rapidly  falling  into  dis- 
credit, and  physiologists  so  eminent  as  Vulpian  and 
Wundt  have  explicitly  announced  their  adhesion  to  the 
principle  of  identity, —  a  principle  which,  as  Vulpian  truly 
remarks,  dominates  the  whole  physiology  of  the  nervous 
system.* 

THE   HYPOTHESIS   OF   SPECIFIC    ENERGIES. 

63.  One  development  of  the  theory  of  Bell,  respecting 
the  different  kinds  of  nerve,  has  been  the  still  accredited 
hypothesis  that  each  nerve  has  a  "  specific  energy,"  or  qual- 
ity, in  virtue  of  which  it  acts  and  reacts  only  in  one  way. 
The  optic  nerve,  no  matter  how  stimulated,  only  responds 
by  a  sensation  of  color,  the  auditory  nerve  only  by  a  sen- 
sation of  sound  ;  and  so  on.  This  hypothesis,  which  (as  I 
learn  from  a  correspondent)  f  was  originally  propounded 
by  Bell  himself,  was  developed  and  made  an  European 
doctrine  by  Johannes  Mliller,  first  in  his  remarkable  trea- 
tise, tlhcr  die  'plicmtastisclien  Gesichtsersclicimtngcn  (1826), 

*  "  J'espeieVous  convaincre  que  tovis  les  elements  anatomiques  dcs  nerfs 
sensitifs,  motciirs,  vasomoteurs,  et  autrcs,  ont  les  memes  proprietes,  et  ne 
sont  distincts  que  par  leurs  fonctions.  Cette  question  est  de  la  plus 
haute  importance  pour  la  physiologie  generale.  C'est  celle  qui  domine 
toute  la  phj'siologie  dcs  fibres  nerveuses."  —  VULPIAN,  Ler^ons  sur  la 
Physiologie  dii  Systimc  Nervciix,  p.  1 1 . 

t  Mr.  James  Andi-.ews. 


208  THE   niYSICAL   BASIS   OF   MIND. 

and  afterwards  in  his  Physiology.  Like  all  good  hypoth- 
eses, it  has  been  iVuitlul ;  and  Helmholtz  still  holds  it  to 
be  of  extraordinary  importance  i'or  the  theory  of  percep- 
tion. Although  combated  by  a  few  physiologists,  it  has 
kept  its  place  firm  in  the  general  acceptance ;  no  doubt 
because  it  I'orms  a  ready  explanation  of  the  facts.  But,  as 
I  often  have  to  remark,  explanation  is  not  dcmonstratio7i* 

64.  The  first  criticism  to  be  made  on  tlie  hypothesis  is 
that  it  commits  the  error  of  confounding  function  with 
property,  assigning  as  a  specific  quality  of  the  nerve  the 
reaction  of  the  organ  innervated.  Thus  Mliller  speaks  of 
the  specific  energy  as  "  the  essential  condition  of  the 
nerves  in  virtue  of  which  they  see  light  and  hear  sound." 
But  the  optic  nerve  no  more  sees,  than  the  liver-nerve 
secretes  bile.  That  the  optic  nerve  is  one  element  in  the 
mechanism  on  which  vision  depends,  is  all  that  we  can 
say.  Midler  declares  that  it  is  not  sufficient  to  assume 
each  nerve  to  be  so  constituted  that  it  has  a  susceptibility 
to  certain  stimuli  rather  than  to  others ;  but  that "  with 
Aristotle  we  must  ascribe  to  each  a  peculiar  energy  as  its 
vital  quality.  Sensation,"  he  adds,  "  consists  in  the  sen- 
sorium  receiving  through  the  medium  of  the  nerves  a 
knowledge  of  certain  qualities,  —  a  condition,  not  of  the 
external  bodies,  but  of  the  nerves  themselves,"  —  and 
these  qualities  are  different  in  different  nerves.  In  other 
words,  he  assumes  a  special  substance  for  each  special 
energy.  The  sensation  of  color  depends  on  the  spe- 
cial Visual  substance  {Sehsinnsulstanz)  ;  the  sensation 
of  sound  on  the  Auditory  substance  {Horsinnsubstanz) ; 
and  so  on. 

65.  We  have  here  an  hypothesis  analogous  to  that  of 
Innate  Ideas,  or  a  priori  Forms  of  Thought.  It  is,  in  fact, 
only  a  reproduction  of  that  conception  carried  into  the 

*  In  the  second  number  of  Za  Revue  Philosophique,  Paris,  1876,  I  have 
treated  this  question  of  specific  energies  more  at  length  than  I  could  find 
space  for  in  the  present  volume. 


THE  NERVOUS  MECHANISM.  209 

sphere  of  Sense.  No  one  thinks  of  assigning  specific 
energies  to  the  several  muscles,  yet  a  movement  of  pre- 
hension is  as  different  from  a  movement  of  extension,  a 
peristaltic  movement  is  as  different  from  a  movement 
of  occlusion,  as  a  sensation  of  sound  is  from  a  sensation  of 
color.  If  movement  is  common  to  both  of  the  one  class, 
feeling  is  common  to  both  of  the  other:  the  forms  and 
mechanism  are  different  and  specific.  Muscles  have  the 
common  property  of  contracting  under  stimulation  ;  what- 
ever be  the  nature  of  the  stimulus,  each  muscle  has  its 
own  particular  response,  or  mode  of  reaction :  the  Hexor 
always  bending,  never  extending  the  limb ;  the  sphincter 
always  closing,  never  opening  the  orifice.  The  move- 
ments of  the  heart  are  not  the  same  as  those  of  tlie  eye ; 
both  are  unlike  the  movements  of  the  intestine.  There 
are  muscles  which  respond  to  some  stimuli,  and  not  to 
others.  Those  of  the  eye,  or  of  the  vocal  chords,  respond 
to  impulses  which  would  leave  the  niasseter  or  biceps 
unstirred.  According  to  Marey,  the  liyoglossus  of  a  frog 
will  become  tetanic  under  a  stimulus  of  only  ten  pulses  in 
a  second ;  whereas  the  gastrocnemius  of  that  same  frog 
resists  a  stimulus  of  less  than  twenty  in  a  second.  We 
find  the  retina  responding  to  ethereal  pulses  which  leave 
the  auditorius  unaffected ;  we  find  the  muscles  of  a  gnat's 
wing  so  exquisitely  susceptible  that  the  wing  beats  eight 
thousand  times  in  a  second,  —  a  delicacy  in  comparison 
with  wliich  even  our  muscles  of  the  eye  are  coarse. 

66.  The  facts  which  the  hypothesis  of  specific  energies 
is  called  on  to  explain  are  more  consistently  interpreted 
on  the  admission  of  a  common  property  in  nerve-tissue, 
manifesting  different  degrees  of  excitability,  and  entering 
into  different  mechanisms,  so  that  the  functional  results 
differ.  A  nerve  which  may  be  stimulated  from  the  skin 
will  not  respond  at  all,  or  not  in  the  same  way,  if  the 
stimulus  be  applied  under  the  skin.     Are  we  to  suppose 


210  THE  niYsicAL  basis  of  mind. 

that  the  specific  energy  resides  in  one  part  of  the  nerve, 
antl  not  in  another  ?  *  Tiiat  the  optic  nerve  responds  to 
stimuli  whicli  will  not  sensibly  excite  a  motor  nerve, 
depends  on  the  terminal  structures  through  Avhich  the 
stimulation  is  excited  ;  for  the  optic  nerve  itself,  apart 
from  the  retinal  expansion,  is  as  insensible  to  light  as  the 
motor  nerve  is.  And  the  specific  sensation,  or  movement, 
which  results  from  stimulation  of  a  nerve  depends  not  on 
the  nerve,  but  on  the  mechanism  of  which  the  nerve  is 
one  element.  Sensations  of  touch,  temperature,  and  pain 
are  assuredly  specific ;  they  are  as  unlike  each  other  as 
a  sensation  of  taste  is  unlike  a  sensation  of  smell.  Yet 
the  same  nerves,  variously  stimulated,  produce  all  three 
sensations. 

67.  We  conclude,  therefore,  that  the  phrase  "specific 
energy"  is  an  elliptical  expression  for  the  particular  office 
of  a  nerve.  In  this  meaning  there  is  no  obscurity.  The 
optic  nerve  is  not  a  vasomotor  nerve,  the  skin  nerve  is 
not  a  muscle  nerve ;  the  auditory  nerve  is  a  nerve  of 
special  sensation,  the  vagus  is  a  nerve  of  systemic  sen- 
sation ;  and  so  on.  Neither  movement  nor  sensation  be- 
longs to  the  nerves  themselves. 

*  In  1859  I  mentioned  that  if  the  nerves  of  a  frog's  back  he  exposed  by 
raising  the  skin,  they  may  be  pricked  or  even  cut  without  sensible  effect, 
although  a  slight  prick  on  the  skin  -will  excite  the  nerves,  and  cause 
a  reflex  action.  In  1870,  Prof.  FiCK  expressed  his  astonishment  at 
finding  that  after  he  had  cut  out  a  piece  of  the  skin,  leaving  it  attached 
to  the  body  by  a  single  nerve,  electrical  stimulation  of  this  excised  skin 
caused  the  frog  to  make  the  reflex  movement  of  rubbing  the  irritated  sur- 
face ;  whereas  electrical  stimulation  of  the  nerve-trunk  itself  produced  no 
reflex  effect,  only  a  twitching  of  a  muscle.  PJliigcrs  Archiv,  1870,  p. 
327.  Browx  S6QUARD  tries  to  establish  a  distinct  species  of  nerves 
as  conductors  of  sensitive  impressions,  from  those  which  are  imiyrcssion- 
ablc.  The  facts  on  which  he  founds  these  two  properties  simply  show 
that  nerves  are  so  disposed  that  the  stimulus  which  excites  them  in 
one  place  fails  in  another.  He  could  hardly  maintain  that  a  skin 
nerve  contained  impressionable  fibres  at  its  periphery,  and  only  con- 
ducting fibres  in  its  trunk  ?  See  his  communication  to  the  Eoyal  Society, 
Proceedings,  1856  ;  and  Lectures  in  the  Lancet,  lOtli  July,  1858. 


THE  NERVOUS  MECHANISM.  211 


CHAPTER    IV. 

SENSIBILITY. 

68.  The  principles  laid  down  in  the  preceding  chapter 
are  equally  applicable  to  the  central  system.  But  here 
greater  difficulties  await  us.  We  cannot  expect  tradi- 
tional views  to  be  easily  displaced,  when  they  have 
taken  such  hold  on  the  mind,  as  is  the  case  with  regard 
to  Sensibility.  To  admit  that  all  nerves  have  a  common 
property,  and  that  their  functional  relations  depend  on 
tlie  organs  which  they  innervate,  demands  small  relin- 
quishment of  cherished  opinions.  But  to  admit  that 
all  nerve-centres  have  a  common  property,  and  that  their 
functional  relations  depend  on  their  anatomical  connec- 
tions, is  to  sweep  away  at  once  a  mass  of  theoretic  in- 
terpretations which  from  long  familiarity  have  acquired 
an  almost  axiomatic  force.  That  the  brain,  and  the  brain 
only,  is  the  source  and  seat  of  Sensibility  is  the  postulate 
of  modern  Physiology. 

69.  The  question  is  one  of  extreme  complexity,  but 
may  be  greatly  simplified,  if  we  can  manage  to  reduce  it 
to  purely  physiological  terms,  and  consider  the  phenome- 
na in  their  objective  aspect.  In  dealing  with  nerves  and 
their  actions  this  was  comparatively  easy ;  we  had  for 
the  most  part  only  physiological  processes  to  unravel. 
It  is  otherwise  in  dealing  with  nerve-centres  —  the  sub- 
jective or  psychological  aspect  of  the  phenomena  inevi- 
tably tln-usts  itself  on  our  attention ;  and  all  the  mys- 
teries of  Feeling  and  Thought  cloud  our  vision  of  the 


•212  THE   niYSICAL   BASIS   OF    MIND. 

neural  process.  Do  what  we  will,  we  cannot  altogetlier 
divest  Sensibility  of  its  psychological  connotations,  can- 
not help  intei'preting  it  in  terms  of  Consciousness ;  so 
that  even  when  treating  of  sensitive  phenomena  ob- 
served in  molluscs  and  insects,  we  always  imagine  these 
more  or  less  suffused  with  Feeling,  as  tliis  is  known  in 
our  own  conscious  states. 

70.  Feeling  is  recognized  as  in  some  way  or  other 
bound  up  with  neural  processes ;  but  Physiology  proper 
has  only  to  concern  itself  with  the  processes ;  and  the 
question  whether  these  can,  and  do,  go  on  unaccompa- 
nied by  Feeling,  is,  strictly  speaking,  one  which  belongs 
to  Psychology.  It  demands  as  a  preliminary  that  the 
term  Feeling  be  defined ;  and  the  answer  will  depend 
upon  that  definition,  namely,  whether  Feeling  be  inter- 
preted as  synonymous  with  Consciousness  in  the  re- 
stricted sense,  or  synonymous  with  the  more  general  term 
Sentience.  If  the  former,  then  since  there  are  unques- 
tionably neiu'al  processes  of  which  we  are  not  conscious, 
we  must  specify  the  particular  groups  which  subserve 
Feeling ;  as  we  specify  the  particular  groups  which  sub- 
serve the  sensations  of  Sight,  Hearing,  Taste,  etc.;  and 
localize  the  separate  functions  in  separate  organs.  If  the 
latter,  then,  since  all  neural  processes  have  a  common 
character,  we  have  only  to  localize  the  particular  varia- 
tions of  its  manifestation,  and  distinguish  sensitive  phe- 
nomena as  we  distinguish  motor  phenomena. 

71.  It  is  absolutely  certain  that  the  Feeling  we  attrib- 
ute to  a  mollusc  is  different  from  that  which  we  attrib- 
ute to  a  man ;  if  only  because  the  organisms  of  the  two 
are  so  widely  different,  and  have  been  under  such  differ- 
ent conditions  of  excitation.  If  every  feeling  is  the  func- 
tional result  of  special  organic  activities,  varying  with 
the  co-operant  elements,  we  can  ha\e  no  more  warrant 
for  assuming  the  existence  of  the  same  particular  forms 


THE  NERVOUS  MECHANISM.  213 

of  Feeling  in  organisms  that  are  unlike,  than  for  assum- 
ing the  47th  proposition  of  Euclid  to  be  presented  by  any 
three  straight  lines.  The  lines  are  tlie  necessary  basis 
for  the  construction,  but  they  are  not  the  triangle,  ex- 
cept when  in  a  special  configuration.  This  is  not  deny- 
ing that  animals  fed  (in  the  general  sense  of  that  term), 
it  is  only  asserting  that  their  feelings  must  be  very  unlike, 
our  own.  Even  in  our  own  race  we  see  marked  differ- 
ences —  some  modes  of  feeling  being  absolutely  denied 
to  individuals  only  slightly  difiering  from  their  fellows. 
If,  however,  we  admit  that  different  animals  must  have 
different  modes  of  Feeling,  we  must  also  admit  that  the 
neuro-muscular  activities  are  generically  alike  in  all, 
because  of  tlie  fundamental  similarity  in  the  structures. 
Whether  we  shall  assign  Feeling  to  the  mollusc  or  not 
will  depend  on  the  meaning  of  the  terra ;  but,  at  all 
events,  we  require  some  term  general  enough  to  include 
the  phenomena  manifested  by  the  mollusc,  and  those 
manifested  by  all  other  animals.  Sensibility  is  the  least 
objectionable  terra.  Unless  we  adopt  some  such  general 
designation,  physiological  and  psychological  interpreta- 
tions become  contradictory  and  obscure.  The  current 
iloctrine  which  assigns  Sensibility  to  the  brain,  denying 
it  to  all  other  centres,  is  seriously  defective,  inasnmch 
as  it  implies  tliat  tissues  similar  in  kind  have  utterly 
diverse  properties;  in  other  words,  that  the  same  nerve- 
tissue  which  manifests  Sensibility  in  the  brain  has  no 
such  property  in  the  spinal  cord. 

72.  How  is  this  tenable  ?  No  one  acquainted  at  first 
hand  with  the  facts  denies  that  the  objective  phenomena 
exhibited  Ijy  the  brainless  animal  liave  the  same  general 
character  as  those  of  tlie  animal  possessing  a  brain :  the 
actions  of  tlie  two  are  identical  in  all  cases  which  admit 
of  comparison.  That  is  to  say,  the  objective  appearances 
are  the  same ;  differing  only  in  so  far  as  the  mechanisms 


214  THE  niYSiCAL  basis  of  mind. 

are  made  different  by  the  presence  or  absence  of  certain 
parts.  The  brain  not  being  a  necessary  part  of  the  me- 
chanical adjustments  in-  swimming,  or  pushing  aside  an 
irritating  object,  the  brainless  frog  swims  and  defends  it- 
self in  the  same  way  as  the  normal  frog.  But  no  sooner 
do  we  pass  from  the  objective  interpretation,  and  intro- 
duce the  subjective  element  of  Feeling  among  the  series 
of  factors  necessary  to  the  product — no  sooner  do  we  ask 
whether  the  brainless  frog  fceh  the  irritation  against 
which  it  struggles,  or  wills  the  movements  by  which  it 
swims — than  the  question  has  shifted  its  ground,  and  has 
passed  from  Physiology  to  Psychology.  The  appeal  is  no 
longer  made  to  Observation,  but  to  Interpretation.  Ob- 
servation tells  us  here  nothing  directly  of  Feeling.  What 
it  does  tell  us,  however,  is  the  identity  of  the  objective 
phenomena;  and  Physiology  demands  that  a  common 
term  be  employed  to  designate  the  character  common  to 
the  varied  phenomena.  Sensibility  is  such  a  term.  But 
most  modern  physiologists,  under  the  bias  of  tradition, 
refuse  to  extend  Sensibility  to  the  spinal  cord,  in  spite 
of  the  evidences  of  the  spinal  cord  possessing  that  prop- 
erty in  common  with  the  brain.  They  prefer  to  invoke 
a  new  property ;  they  assign  spinal  action  to  a  Eeflex 
Mechanism  which  has  nothing  of  the  character  of  Sen- 
sibility, because  they  have  identified  Sensibility  with 
Consciousness,  and  have  restricted  Consciousness  to  a 
special  group  of  sensitive  phenomena. 

73.  Nor  is  it  to  be  denied  that  on  tliis  ground  they 
have  a  firm  basis.  Every  one  could  testify  to  the  fact 
that  many  processes  normally  go  on  without  being  accom- 
panied by  consciousness,  in  the  special  meaning  of  the 
term.  Eeflex  actions, —  such  as  winking,  breathing,  swal- 
lowing,—  notoriously  produced  by  stimulation  of  sensi- 
tive surfaces,  take  place  without  our  "  feeling  "  them,  or 
being  "  conscious  "  of  them.     Hence  it  is  concluded  that 


THE  NERVOUS  MECHANISM.  215 

the  Eeflex  mechanism  suffices  without  the  intervention  of 
Sensibility.  I  altogether  dispute  the  conclusion ;  and  in 
a  future  Problem  will  endeavor  to  show  that  Sensibility 
is  necessary  to  Reflex  Action.  But  without  awaiting  that 
exposition  we  may  at  once  confront  the  evidence,  by  ad- 
ducing the  familiar  fact  that  "  unconscious  "  processes  go 
on  in  the  brain  as  well  as  in  the  s]3inal  cord  ;  and  this  not 
simply  in  the  sphere  of  Volition,  but  also  in  the  sphere  of 
Thought.*  We  act  and  think  "  automatically  "  at  times, 
and  are  quite  "  unconscious "  of  what  we  are  doing,  or 
of  the  data  we  are  logically  grouping.  We  often  think 
as  unconsciously  as  we  breathe ;  although  from  time  to 
time  we  become  conscious  of  both  processes.  Yet  who 
will  assert  that  these  unconscious  processes  were  inde- 
pendent of  Sensibility  ?  Who  will  maintain  that  because 
cerebral  processes  are  sometimes  unaccompanied  by  that 
peculiar  state  named  Consciousness,  therefore  all  its  pro- 
cesses are  unaccompanied  by  Feeling  ?  And  if  here  we 
admit  that  the  Reflex  mechanism  in  the  brain  is  a  sensitive 
mechanism,  surely  we  must  equally  admit  that  the  similar 
Reflex  mechanism  in  the  spinal  cord  is  sensitive  ? 

74.  Let  it  be  understood  that  Sensibility  is  the  com- 
mon property  of  nerve-centres,  and  physiological  inter- 
pretations will  become  clear  and  consistent.  Conscious- 
ness, as  understood  by  psychologists,  is  not  a  property  of 
tissue,  it  is  a  function  of  the  organism,  dependent  indeed 
on  Sensibility,  but  not  convertible  with  it.  There  is  a 
greater  distinction  between  the  two  than  between  Sensa- 
tion, the  reaction  of  a  sensory  organ,  and  Perception,  the 

*  In  conseriuenoe  of  tliis  observation  some  pliysiologists  liave  main- 
tained that  Feeling  or  Consciousness  never  arises  in  cerebral  activity, 
unless  the  thalami  and  the  connected  tracts  are  at  the  same  time  in 
action.  I  go  further,  and  maintain  that  there  is  no  Consciousness  (in 
the  restricted  meaning  of  the  term)  un/eas  the  whole  onjanism  is  involved. 
Cerebral  or  spinal  activity  will  be  activity  of  Sensibility ;  but  this  is  only 
the  basis  of  Consciousness. 


210  TlIK   rilYSICAL   BASIS   OF   MIND. 

combined  result  of  sensory  and  cerebral  reactions ;  or 
than  that  between  Contractility,  the  property  of  the  mus- 
cles, and  Flying,  the  function  of  a  particular  group  of 
muscles.  It  is  not  possible  to  have  Consciousness  with- 
out Sensibility ;  but  perfectly  possible  to  have  Sensations 
without  Consciousness.  This  will  perhaps  seem  as  incon- 
ceivable to  the  reader  as  it  seemed  to  Schroder  van  der 
Kolk.* 

75.  Let  us  illustrate  it  by  the  analogy  of  Pain.  There 
is  a  vast  amount  of  sensation  normally  excited  which  is 
totally  unaccompanied  by  the  feelings  classed  as  painful. 
The  action  of  the  special  senses  may  be  exaggerated  to  an 
intolerable  degree,  but  the  exaggeration  never  passes  into 
pain  :  the  retina  may  be  blinded  with  excess  of  light,  and 
the  ear  stunned  with  sound  —  the  optic  nerve  may  be 
pricked  or  cut  —  but  no  pain  results.  The  systemic  sen- 
sations also  are  habitually  painless,  though  they  pass  into 
pain  in  abnormal  states.  Clearly,  then,  Pain  is  not  the 
necessary  consequence  of  Sensibility ;  and  this  is  true  not 
only  of  certain  sensitive  parts,  but  of  all ;  as  is  proved  in 
the  well-known  facts  of  Analgesia,  in  which  complete 
insensibility  of  the  skin  as  regards  Pain  co-exists  with 
vivid  sensibility  as  regards  Touch  and  Temperature. 
Hence  the  majority  of  physiologists  refuse  to  acknowl- 
edge that  the  struggles  and  cries  of  an  animal,  after 
removal  of  the  brain,  are  evidences  of  pain ;  maintaining 
that  they  are  "  simply  reflex  actions."  This  is  probable  ; 
the  more  so  as  we  know  the  struggles  and  cries  which 
tickling  will  produce,  yet  no  pain  accompanies  tickling. 
But  if  the  struggles  and  cries  are  not  evidence  of  pain, 
they  are  surely  evidence  of  Sensibility. 

76.  Now  for  the  term  Pain  in  the  foregoing  paragraph 

*  "An  unconscious  sensation,  which  Lewes  distinguishes  from  percep- 
tion, is  to  me  an  inconceivable  (ist  fiir  mich  ein  Unding)." — Schroder 
VAN  DKR  Kolk,  Die  Pathologic  dcs  Geistcs-Krankhciten,  p.  22. 


THE  NERVOUS  MECHANISM.  217 

substitute  the  terra  Consciousness,  and  you  will  perhaps 
allow  that  while  it  may  be  justifiable  to  interpret  the 
actions  of  a  brainless  animal  as  due  to  a  mechanism 
which  is  unaccompanied  by  the  specially  conditioned  forms 
of  Sensibility  classed  under  Consciousness — just  as  it 
is  unaccompanied  by  the  specially  conditioned  forms  of 
Perception  and  Emotion  —  there  is  no  justification  for 
assuming-  the  mechanism  not  to  have  been  a  sensitive 
mechanism.  The  wingless  bird  cannot  manifest  any  of 
the  phenomena  of  flight;  but  we  do  not  therefore  deny 
that  its  other  movements  depend  on  Contractility. 

77.  Difficult  as  it  must  be  to  keep  the  physiological 
question  apart  from  the  psychological  when  treating  of 
Sensibility,  we  shall  never  succeed  in  our  analysis  unless 
the  two  questions  are  separately  treated.  The  physiolo- 
gist considers  organisms  and  their  actions  from  their 
objective  side,  and  tries  to  detect  the  mechanism  of  the 
observed  phenomena.  These  he  has  to  interpret  in  terms 
of  Matter  and  Motion.  The  psychologist  interprets  them 
(in  terras  of  Feeling.  The  actions  which  we  see  in  others 
we  cannot  feel,  except  as  visual  sensations ;  the  changes 
which  we  feel  in  ourselves  we  cannot  see  in  others,  except 
as  bodily  movements.  The  reaction  of  a  sensory  organ 
is  by  the  physiologist  called  a  sensation,  —  borrowing  the 
term  from  the  psychologist ;  he  explains  it  as  due  to  the 
stimulus  which  changes  the  molecular  condition  of  the 
organ ;  and  tliis  changed  condition,  besides  being  seen  to 
be  followed  by  a  muscular  movement,  is  inferred  to  be 
accompanied  by  a  change  of  Feeling.  The  psychologist 
has  direct  knowledge  only  of  the  change  of  Feeling  which 
follows  on  some  other  change ;  he  infers  that  it  is  origi- 
nated by  the  action  of  some  external  cause,  and  infers  that 
a  neural  process  precedes,  or  accompanies,  the  feeling. 
Obviously  there  are  two  distinct  questions  hero,  involving 
distinct  methods.     The  physiologist  is  compelled  to  com- 

VOL.  III.  10 


"218  THE  PHYSICAL  basis  of  mind. 

plete  his  objective  observations  by  subjective  suggestions; 
compelled  to  add  Feeling  to  the  terms  of  Matter  and 
Motion,  iu  spite  of  the  radical  diversity  of  their  aspects. 
The  psychologist  also  is  compelled  to  complete  his  sub- 
jective observations  by  objective  interpretations,  linking 
the  internal  changes  to  the  external  changes.  A  complete 
theory  nmst  harmonize  the  two  procedures. 

78.  In  a  subsequent  Problem  we  shall  have  to  examine 
the  nature  of  Sensation  in  its  psychological  aspect ;  here 
we  have  first  to  describe  its  physiological  aspect.  To  the 
psychologist,  a  sensation  is  simply  a  fact  of  Conscious- 
ness ;  he  has  nothing  whatever  to  do  with  the  neural  pro- 
cess, which  the  physiologist  considers  to  be  the  physical 
basis  of  this  fact ;  and  he  therefore  regards  the  physiolo- 
gists as  talking  nonsense  when  they  talk  of  "  unconscious 
sensations,"  the  phrase  being  to  him  equivalent  to  "unfelt 
feelings,"  or  "invisible  light."  It  is  quite  otherwise  with 
the  physiologist,  who  viewing  a  sensation  solely  as  a  neu- 
ral process,  the  reaction  of  a  sensory  organ,  can  lawfully 
speak  of  unconscious  sensations,  as  the  physicist  can 
speak  of  invisible  rays  of  light,  —  meaning  those  rays 
which  are  of  a  different  order  of  undulation  from  the  vis- 
ible rays,  and  which  may  become  visible  when  the  sus- 
ceptibility of  the  retina  is  exalted.  He  knows  that  there 
are  different  modes,  and  different  complexities  of  neural 
process ;  to  one  class  he  assigns  consciousness,  to  the 
other  unconsciousness.  If  he  would  be  severely  precise, 
he  would  never  speak  of  sensation  at  all,  but  only  of  sen- 
sory reaction.  But  such  precision  would  be  pedantic 
and  idle.  He  wants  the  connotations  of  the  term  sensa- 
tion, and  therefore  uses  it. 

79.  The  functional  activity  of  a  gland  is  stimulated  by 
a  neural  process  reflected  from  a  centre ;  by  a  similar 
])rocess  a  muscle  is  called  into  action.  No  one  supposes 
that  the  neural  process  is  in  the  one  case  secretory,  in  the 


THE  NERVOUS  MECHANISM.  219 

other  motory:  in  both  it  is  the  same  process  in  the  nerve; 
and  our  investigation  of  it  would  be  greatly  hampered  if 
we  did  not  disengage  it  from  all  the  suggestions  hovering 
around  the  ideas  of  secretion  and  muscular  action.  In 
like  manner  we  must  disengage  the  neural  process  of  a 
sensory  reaction  from  all  the  suggestions  hovering  around 
the  idea  of  Consciousness,  when  that  term  designates  a 
complex  of  many  reactions.  In  Problem  III.  we  shall 
enter  more  particularly  into  the  distinction  between  Sen- 
sibility and  Consciousness;  for  the  present  it  must  suffice 
to  say  that  great  ambiguity  exists  in  the  current  usage 
of  these  terms.  Sometimes  Consciousness  stands  as  the 
equivalent  of  Sensibility ;  sometimes  as  a  particular 
mode  of  Sensibility  known  as  Eeflection,  Attention,  and 
Thought.  The  former  meaning  is  an  extension  of  the 
term  similar  to  that  given  to  the  word  Eose,  which  origi- 
nally meaning  Red  came  to  be  restricted  to  a  particular 
red  flower ;  and  after  other  flowers  of  the  same  kind  were 
discovered  which  had  yellow  and  white  petals,  instead  of 
red,  the  term  rose  still  adhered  even  to  these.  "Yellow 
Rose  "  is  therefore  as  great  a  verbal  solecism"  as  uncon- 
scious sensation.  We  have  separated  the  redness  from 
the  rose,  and  can  then  say  that  the  color  is  one  thing,  the 
flower  another.  By  a  similar  process  of  abstraction  we 
separate  Consciousness  from  Sensation,  and  we  can  then 
say  that  there  are  sensations  without  consciousness.  In 
consequence  of  this,  psychologists  often  maintain  that  to 
liave  a  sensation  and  be  conscious  of  it  are  two  diflerent 
states.  We  are  said  to.  hear  a  sound,  and  yet  not  to  be 
conscious  of  hearing  it.  The  sound  excites  a  movement, 
but  it  does  not  excite  our  consciousness.  Now  although 
it  is  true  that  there  are  roses  wliich  are  not  red,  it  is  not 
true  that  there  are  roses  which  have  no  color  at  all.  Al- 
though it  is  true  that  there  are  sensations  which  are  not 
of  the  particular  mode  of  Sensibility  whicli  psychologists 


220  THE   niYSICAL   BASIS   OF   MIND. 

specially  designate  as  Consciousness,  it  is  not  true  that 
there  are  sensations  which  are  not  modes  of  Sensibility. 

80.  And  what  is  Sensibility  which,  on  its  sul)jective 
side,  is  Sentience  ?  In  one  sense  it  may  be  answered 
that  we  do  not  know.  In  another  sense  it  is  that  which 
we  know  most  clearly  and  positively  :  Sentience  forms  the 
substance  of  all  knowledge.  Being  the  ultimate  of  knowl- 
edge, every  effort  must  be  vain  which  attempts  to  explain 
it  by  reduction  to  simpler  elements.  The  human  mind, 
impatient  of  ultimates,  is  always  striving  to  pierce  beyond 
the  fundamental  mysteries ;  and  this  impatience  leads  to 
the  attempts  so  often  made  to  explain  Sensibility  by  re- 
ducing it  to  terms  of  Matter  and  Motion.  But  inasmuch 
as  a  clear  analysis  of  Matter  and  Motion  displays  that  our 
knowledge  of  these  is  simply  a  knowledge  of  modes  of 
Feeling,  the  reduction  of  Sentience  or  Sensibility  to  Mat- 
ter and  Motion  is  simply  the  reduction  of  Sensibility  to 
some  of  its  modes.  This  point  gained,  a  clear  conception 
of  the  advantages  of  introducing  the  ideas  of  Matter  and 
Motion  will  result.  It  will  then  be  the  familiar  and  in- 
dispensable method  of  explaining  the  little  known  by  the 
better  known.  The  objective  asjDect  of  things  is  com- 
monly represented  in  the  visible  and  palpable;  because 
what  we  can  see  we  can  also  generally  touch,  and  what 
we  can  touch  we  can  taste  and  smell ;  but  we  cannot 
touch  an  odor  nor  a  sound;  we  cannot  see  them;  we  can 
only  connect  the  odorous  and  sonorous  objects  with  vis- 
ible or  palpable  conditions.  Everywhere  we  find  sensa- 
tions referred  to  visible  or  palpable  causes ;  and  hence  the 
desire  to  find  this  objective  basis  for  every  change  in  Sen- 
sibility. The  sensation,  or  state  of  consciousness,  is  the 
ultimate  fact ;  we  can  only  explain  it  by  describing  its 
objective  conditions. 

81.  Thus  much  on  the  philosophical  side.  Eeturning 
to  our  physiological  point,  we  miist  say  that  a  sensation 


THE  NERVOUS  MECHANISM.  221 

is,  objectively,  the  reaction  of  a  sensory  organ,  or  organ- 
ism ;  subjectively,  a  change  of  feeling.  Objectively  it  is 
a  phenomenon  of  movement,  but  distinguishable  from 
other  phenomena  by  tlie  speciality  of  its  conditions.  It 
is  a  vital  phenomenon,  not  a  purely  mechanical  phenom- 
enon. Although  the  molecular  uiovement  conforms,  of 
course,  to  mechanical  principles,  and  may  be  viewed  ab- 
stractly as  a  purely  mechanical  result,  yet,  because  it 
takes  place  under  conditions  never  found  in  machines,  it 
has  characters  which  markedly  separate  it  from  the  move- 
ments of  machines.  Among  these  differential  characters 
may  be  cited  that  of  selective  adaptation,^'  which  is  most 
conspicuous  in  volition. 

82.  In  the  early  stages  of  animal  evolution  there  is 
no  differentiation  into  muscle  and  nerve.  The  whole 
organism  is  equally  sensitive  (or  irritable)  in  every  part. 
Muscles  appear,  and  then  they  are  the  most  sensitive 

*  Bj''  selective  adaptation  is  meant  the  varying  combination  of  motor 
impulses  to  suit  the  varying  requirements  of  the  effect  to  be  produced. 
Physical  mechanisms  are  limited  to  the  performance  of  definite  actions  ; 
sensitive  mechanisms  employ  fluctuating  combinations  of  elements  in 
response  to  fluctuations  of  stimuli.  The  wheels,  levers,  springs,  and 
valves  of  a  machine  cannot  be  diff"erently  combined  according  to  varying 
degrees  of  the  motor-force,  as  the  nerves  and  muscles  of  an  organism  are 
differently  combined  by  varying  sensations.  An  automaton  may  be  con- 
structed to  ])lay  on  the  violin,  but  it  will  only  play  the  air  to  which  it  is 
set;  it  cannot  vary  tlie  performance,  —  cannot  play  a  fivlse  note,  or  throw 
in  a  crescendo  here,  a  largo  there,  according  to  a  caprice  of  feeling.  We 
must  admit  that  a  violinist  has  his  delicate  and  changing  movements 
guided  by  sensations,  auditory  and  muscular ;  any  interrujition  in  the 
.sensations  would  arrest  the  movements,  which  in  truth  incorporate  them. 
And  yet  it  is  well  known  that  the  violinist  m.iy  perform  while  completely 
"  unconscious."  I  do  not  simply  refer  to  the  fact  that  his  thouglits  and 
attention  may  be  elsewhere;  I  refer  to  such  facts  as  are  recorded  in 
Pathology.  Thousseau,  for  example,  had  an  epileptic  patient  who  was 
occasionally  .seized  with  attacks  of  complete  unconsciousness  while  he  was 
performing  in  the  orchestra;  yet,  on  reawakening  to  consciousness,  he 
found  tliat  Ik;  had  continued  to  play,  had  kept  proper  time,  and  played 
the  proper  notes. 


222  TllH    PHYSICAL   BASIS   OF   MIND. 

parts.  Nerves  appear,  and  the  seat  of  Sensibility  has 
been  transferred  to  them  ;  not  that  the  muscles  have  lost 
theirs,  but  their  irritability  is  now  represented  by  their 
dominant  character  of  Contractility,  and  the  nerves  have 
taken  on  the  special  office  of  Sensibility.  That  is  to  say, 
while  both  muscle  and  nerve  form  integral  elements  of 
the  sensitive  reaction,  the  process  itself  is  analytically 
conceived  as  a  combination  of  two  distinct  properties, 
resident  in  two  distinct  tissues. 

83.  Carrying  further  this  analytical  artifice,  I  propose 
to  distinguish  the  central  organs  as  the  seat  of  Sensibility, 
confining  Neurility  to  the  peripheral  nerves.  In  physio- 
logical reality  both  systems,  central  and  peripheral,  are 
one;  the  separation  is  artificial.  Strictly  speaking,  there- 
fore, Neurility  —  or  nerve-action  —  is  the  general  prop- 
erty of  nerve-tissue,  central  and  peripheral.  But  since 
Neurility  may  be  manifested  by  nerves  apart  from  cen- 
tres, whereas  Sensibility  demands  the  co-operation  of 
both,  and  since  we  have  often  to  consider  the  central 
process  in  itself,  without  attending  to  the  process  in  the 
nerves,  it  is  well  to  have  two  characteristic  terms.  I 
shall  therefore  always  use  the  term  Sensibility  for  the 
reactions  of  the  nervous  centres,  —  Sentience  being  its 
psychological  equivalent;  although  the  reader  will  un- 
derstand that  in  point  of  fact  there  is  no  break,  nor 
transformation,  as  the  wave  of  change  passes  from  sen- 
sory nerve  to  centre,  and  from  centre  to  motor  nerve : 
there  is  one  continuous  process  of  change.  But  just  as 
we  analytically  distinguish  the  sensory  from  the  motor 
element  of  this  indissoluble  process,  so  we  may  distin- 
guish the  ingoing  and  outgoing  stages  from  the  combining 
stage.  Sensibility,  then,  represents  the  property  of  com- 
bining and  grouping  stimulations. 

84.  Fully  aware  of  the  misleading  connotations  of  the 
term,  and  of  the  difficulty  which  will  be  felt  in  disen- 


THE  NEKVOUS  MECHANISM.  223 

gaging  it  from  these,  especially  in  reference  to  Conscious- 
ness, I  have  long  hesitated  before  adopting  it.  But  the 
advantages  greatly  outweigh  the  disadvantages.  Sensi- 
bility has  long  been  adndtted  to  express  the  peculiar 
modes  of  reaction  in  plants  and  animals  low  down  in  the 
scale.  No  one  hesitates  to  speak  of  a  sensitive  jolant,  or 
a  sensitive  surface.  The  tentacles  of  a  polype  are  said  to 
be  sensitive  ;  though  probably  no  one  thereby  means  that 
the  polype  has  what  psychologists  mean  by  Consciousness. 
By  employing  the  general-  term  Sensibility  to  designate 
the  whole  range  of  reactions  peculiar  to  the  nerve-centres, 
Avhen  tliese  special  organs  exist,  it  will  be  possible  to  in- 
terpret all  the  physiological  and  psychological  phenomena 
observed  in  animals  and  men  on  one  uniform  method. 
The  observed  variations  will  then  be  referable  to  varieties 
in  organisms. 

85.  Suppose,  for  illustration,  an  organism  like  the  hu- 
man except  that  it  is  wholly  deficient  in  Sight,  Hearing, 
Taste,  and  Smell.  It  has  no  sense  but  Touch  —  or  the 
general  reaction  under  contact  with  external  objects.  It 
will  move  on  being  stimulated,  and  will  combine  its 
movements  differently  under  different  stimulations.  It 
will  feel,  and  logically  combine  its  feelings.  But  its 
mass  of  feeling  will  be  made  of  far  simpler  elements  than 
ours ;  its  combinations  fewer ;  and  the  contents  of  its 
Consciousness  so  very  different  from  ours  that  we  are 
unable  to  conceive  what  it  will  be  like ;  we  can  only  be 
sure  that  it  will  not  be  very  like  our  own.  This  trun- 
cated organism  will  have  its  Sensibility ;  and  we  must 
assign  this  property  to  its  central  nerve-tissue,  as  we  as- 
sign our  own.  If  now  we  descend  lower,  and  suppose  an 
organism  with  no  centres  whatever,  but  which  neverthe- 
less displays  evidence  of  Sensibility  —  feelings  and  com- 
binations of  movements  —  we  must  then  conclude  that 
tlie   property  specialized   in  a   particular   tissue  of  the 


224  THE  PHYSICAL  BASIS   OF   MIND. 

highly  difTerentiated  organism  is  here  diffused  through- 
out. 

It  is  obvious  that  the  sensations  or  feelings  of  these 
supposed  organisms  will  have  a  common  character  with 
the  feelings  of  mor^  highly  differentiated  organisms,  al- 
though the  modes  of  manifestation  are  so  various.  If  we 
recognize  a  common  character  in  muscular  movements 
so  various  as  the  rhythmic  pulsation  of  the  heart,  the 
larger  rhythm  of  inspiration  and  expiration,  the  restless 
movements  of  the  eye  and  tongue,  the  complexities  of 
manipulation,  the  consensus  of  movements  in  flying, 
swimming,  walking,  speaking,  singing,  etc.,  so  may  we 
recognize  a  common  character  in  all  the  varieties  of  sen- 
sation. The  special  character  of  a  movement  depends 
on  the  moving  organ.  The  special  character  of  a  sen- 
sation depends  on  the  sensory  organ.  Contractility  is 
the  abstract  term  which  expresses  all  possible  varieties 
of  contraction.  Sensibility  —  or  Sentience  —  is  the  ab- 
stract term  which  expresses  all  possible  varieties  of  sen- 
sation. 

86.  The  view  here  propounded  may  find  a  more  ready 
acceptance  when  its  application  to  all  physiological  ques- 
tions has  been  tested,  and  it  is  seen  to  give  coherence  to 
many  scattered  and  hitherto  irreconcilable  facts.  ]\Iean- 
while  let  a  glance  be  taken  at  the  inconsistencies  of  the 
current  doctrine.  That  doctrine  declares  one  half  of  the 
gray  substance  of  the  spinal  cord  to  be  capable  only  of 
receiving  a  sensitive  stimulation,  the  other  half  capable 
only  of  originating  a  motor  stimulation.  AVe  might  with 
equal  projDriety  declare  that  one  half  of  a  muscle  is  ca- 
pable only  of  receiving  a  contractile  stimulation,  and  the 
other  half  of  contracting.  The  ingoing  nerve,  passing 
from  the  surface  to  the  posterior  part  of  the  spinal  cord, 
excites  the  activity  of  the  gray  substance  into  which  it 
penetrates ;  with  the  anterior  part  of  this  gray  substance 


THE  NERVOUS  MECHANISM.  225 

an  outgoing  nerve  is  connected,  and  through  it  the  exci- 
tation is  propagated  to  a  muscle :  contraction  results. 
Such  are  the  facts.  In  our  analysis  we  separate  the  sen- 
sory from  the  motor  aspect,  and  we  then  imagine  that 
this  ideal  distinction  represents  a  real  separation.  We 
suppose  a  phenomenon  of  Sensibility  independent  of  a 
phenomenon  of  Contractility  —  suppose  the  one  to  be 
"  transformed "  into  the  other  —  and  we  then  marvel 
"  how  during  this  passage  the  excitation  changes  its 
nature."  * 

87.  Before  exerting  ingenuity  in  explaining  a  fact,  it 
is  always  well  to  make  sure  that  the  fact  itself  is  cor- 
rectly stated.  Docs  the  neural  excitation  change  its 
nature  in  passing  from  the  posterior  to  the  anterior  gray 
substance  ?  I  can  see  no  evidence  of  it.  Indeed  the 
statement  seems  to  confound  a  neural  process  with  a 
muscular  process.  The  neural  process  is  one  continuous 
excitation  along  the  whole  line  of  ingoing  nerve,  centre, 
and  outfToincj  nerve,  which  nowhere  ceases  or  changes 
into  another  process,  until  the  excitation  of  the  muscle 
introduces  a  new  factor.  So  long  as  the  excitation  keeps 
within  the  nerve-tissue,  it  is  one  and  the  same  process 
of  change ;  its  issue  in  a  contraction,  a  secretion,  or  a 
change  in  the  conditions  of  consciousness,  depends  on 
the  organs  it  stimulates. 

88.  I  have  already  called  attention  to  the  artificial 
nature  of  all  our  distinctions,  and  the  necessity  of  such 
artifices.     They  are  products  of  that 

' '  Secondary  power 
By  which  we  multiply  distinctions,  then 
Deem  that  our  puny  boundaries  are  tilings 
That  we  perceive,  and  not  that  we  have  niade."  + 

The  distinction  of  Central  and  Peripheral  systems  is  not 

*  Claude  Bernard,  Syddme  Nervcux,  1858,  I.  349. 
t  WonnswoKTiT,  The  Prelude. 

10*  O 


226  THE   niYSICAL   BASIS    OF   MIND. 

simply  anatomical,  it  has  a  physiological  justification  in 
this,  that  the  Central  System  is  the  organ  of  connection. 
Any  one  part  of  it  directly  excited  by  an  ingoing  nerve 
projiagates  that  excitation  throughout  the  whole  central 
mass,  and  thus  affects  every  part  of  the  organism.  There- 
fore we  place  Sensibility  in  it. 

But  this  general  Property  subserves  various  Functions, 
according  as  the  Central  System  is  variously  related  to 
different  organs.  This  fact  has  given  rise  to  the  idea  that 
different  portions  of  the  cerebro-spinal  axis  have  different 
properties  —  which  is  a  serious  error.  What  is  certain  is 
that  the  Cerebrum  must  have  a  different  function  from 
that  of  the  Thalami,  and  the  Cerebellum  one  different 
from  the  Medulla  Oblongata ;  while  that  of  the  Medulla 
Spinalis  is  different  from  all.  Precisely  on  the  same 
grounds  that  a  muscle-nerve  has  a  different  office  from  a 
skin-ner\^e,  or  the  pneumogastric  from  the  acoustic.  But 
all  nerves  have  one  Neurility  in  common ;  all  centres 
have  one  Sensibility  in  common. 


THE  NERVOUS  MECHANISM.  227 


CHAPTEE    V. 

ACTION   WITHOUT   NERVE-CENTRES. 

89.  It  has  long  been  one  of  the  unquestioned  postu- 
lates of  Physiology  that  no  nerve-action  can  take  place 
without  the  intervention  of  a  centre ;  and  as  a  corollary, 
that  all  movement  has  its  impulse  —  reflex  or  volitional 
— from  a  centre.*  The  postulate  rests  on  the  assumption 
that  nerves  derive  their  "  force  "  from  their  centre.  This 
assumption  we  have  seen  to  be  erroneous.  Yet,  in  con- 
sequence of  its  acceptance,  experimenters  have  failed  to 
notice  the  many  examples  of  nerve-action  independent 
of  centres.  Indeed,  except  Schiff,  Goltz,  and  Engelmann, 
I  can  name  no  one  who  has  ventured  to  suggest  that 
movements  may  be  excited  through  nerves  without  the 
co-oi:)eration  of  centres ;  f  nor  have  even  they  explicitly 
formidated  the  conclusion  to  which  their  observations 
point. 

It  is  true  that  the  majority  of  muscular  movements  are 
deternnned  by  a  reflex  from  centres  ;  and  that  any  break 

*  "On  pent  dire  que  tonjours  un  plicnomene  de  mouveriKnit  leeoniiait 
l)our  point  de  depart  une  impression  sensitive."  —  Claude  Behnaud, 
I.  267. 

t  Since  this  was  written  Prof.  Michael  Fo.ster  and  Mr.  Dew  Smith 
liave  published  their  very  important  researclies  on  the  motions  of  the 
lieart,  vvhieh  e.stablish  beyond  a  doubt  that,  in  the  molluscs  at  least, 
there  is  no  co-operation  of  either  centre  or  nerve.  — Proceedings  of  the 
Royal  Society,  18th  March,  1875.  (See  also  Studies  from  the  Physiologi- 
cal Laboratory  nf  Cambridge,  Part  II.,  1876.)  Mr.  Foster  knows  that  I 
had  independently,  and  from  a  totally  diderent  line  of  research,  arrived 
at  the  same  conclusion  respecting  the  heart's  movement. 


228  THE   niYSICAL   BASIS   OF   MIND. 

in  the  triple  process  of  the  ingoing  nerve,  centre,  and 
outgoing  nerve,  prevents  such  movements.  It  is  true 
that  the  more  conspicuous  and  liarmoniously  co-ordinated 
phenomena  belong  to  this  class.  But  it  is  also  demon- 
strable that  many  nerve-actions  may,  and  some  do,  take 
place  by  direct  stimulation  of  the  nerve,  or  direct  stimu- 
lation of  the  muscle,  without  the  intervention  of  a  centre, 
without  even  the  intervention  of  a  ganglion.  This  must 
obviously  be  the  case  in  animals  which  have  no  centres ; 
and  even  in  some  which  have  well-developed  nervous 
centres,  there  is  every  reason  to  believe  that  these  cen- 
tres often  act  rather  in  the  way  of  co-ordinating  than  of 
directly  stimulating  actions. 

90.  I  was  first  led  to  doubt  the  reigning  doctrine  by  a 
surprising  observation  (frequently  repeated)  after  I  had 
removed  the  whole  nervous  centres  from  a  garden  snail 
{Helix  i^omatia).  The  muscular  mass  called  "the  foot" 
was  thrown  into  slow  but  energetic  contraction  whenever 
the  skin  was  pricked  with  the  point  of  a  scalpel,  or  touched 
with  acid ;  nay,  even  when  a  glass  rod  dipped  in  the  acid 
was  brought  close  to,  without  absolutely  touching,  the 
skin,  the  foot  curled  up,  and  then  slowly  relaxed.  The 
same  effect  was  produced  on  the  "mantle"  —  where  there 
was  of  course  no  centre.  But  direct  irritation  of  the  mus- 
cles under  the  skin  produced  no  such  contraction ;  only 
through  the  skin  could  the  stimulation  take  effect.  In 
one  case  I  observed  this  strange  phenomenon  five  hours 
after  removal  of  the  centres.  It  was  a  great  puzzle.  At 
first  I  concluded  that  there  must  be  minute  ganglia  in 
the  skin,  serving  as  reflex-centres.  I  searched  for  them 
in  vain ;  and  although  a  longer  search  on  better  methods 
might  'possihhj  have  detected  ganglionic  cells,  I  soon  re- 
lin([uished  the  search,  because  I  had  other  grounds  for 
believing  tliat  e\'en  the  presence  of  abundant  ganglia 
would  not  suffice,  until  some  better  proof  were  afforded 
that  such  ecansclia  were  reflex-centres. 


THE  NERVOUS  MECHANISM.  229 

91/  That  direct  stimulation  of  the  nerve  suffices  to 
move  the  muscles,  is  familiar  to  all  experimenters.  There 
is  no  centre,  or  ganglion,  in  the  amputated  leg  of  the  frog, 
which  nevertheless  contracts  whenever  the  sciatic  nerve 
is  stimulated.  And  after  the  nerve  has  been  exhausted, 
and  refuses  to  respond  to  any  stimulus,  the  muscle  itself 
may  be  directly  stimulated.  Inasmuch  as  the  movement 
depends  on  the  contractility  of  the  muscles,  a  stimulation 
through  centre,  through  motor-nerve,  or  through  muscle, 
will  be  followed  by  contraction.  Let  us  take  a  clear  case 
of  reflex  action.  The  j)upil  of  the  eye  contracts  when  a 
beam  of  light  falls  on  it,  and  dilates  when  the  beam  is 
shut  off.  The  path  of  the  neural  process  is  normally  this : 
the  light  stimulates  the  optic  nerve,  which  in  turn  stimu- 
lates the  corpora  quadrigemina ;  (here  the  nerves  which 
move  the  eye  are  experimentally  proved  to  be  stimulated;) 
and  it  is  through  these  that  the  pupil  is  caused  to  con- 
tract. If  the  optic  nerve  be  divided,  no  such  reflex  takes 
place  —  proving  that  the  contraction  does  not,  at  least 
normally,  come  from  the  ciliary  ganglion. 

But  now  it  is  matter  of  observation  that  the  pupil  will 
contract  and  dilate  under  the  stimuli  of  light  and  dark- 
ness, when  there  is  no  such  reflex  pathway  open.  Re- 
moval of  the  eye  from  the  body  obliterates  this  path,  cuts 
the  eye  off  from  all  connection  with  the  centre.  Brown 
Sequard  removed  both  eyes  from  a  frog,  placed  one  in  a 
dark  box,  and  left  the  other  exposed  to  the  light :  the 
})upil  of  the  former  was  found  dilated,  that  of  the  latter 
contracted.  On  reversing  the  experiment,  and  placing 
the  eye  with  contracted  pupil  in  the  dark  box,  he  found  it 
there  dilate,  while  the  dilated  pupil  exposed  to  the  light 
contracted.*     In  frogs  with  very  irritable  tissues,  I  have 

*  Comptes  Rcndus  de  la  SociiU  de  Biologic,  1847,  I.  40.  In  1856  he 
showed  that  not  only  were  the  muscles  of  the  iris  directly  stimulated  by 
light  (and  this  not  by  its  calorific  or  chemical  rays),  but  that  sixteen  days 


2o0  THE   niYSICAL   BASIS   OF   MIND. 

found  not  only  llie  jjiipil  contracting,  ;ii'ter  the  whole 
cranial  cavity  has  been  emptied,  but  even  the  eyelid 
close,  on  irritating  the  conjunctiva*  —  yet  this  is  one 
of  the  typical  retlex  actions !  I  am  disposed  to  think 
that  even  the  action  of  swallowing  may  be  faintly  excited 
by  stimulation  of  the  pharynx  of  a  brainless  frog ;  but  I 
have  not  observations  sufiiciently  precise  to  enable  me  to 
speak  confidently.  Goltz  has,  however,  shown  that  after 
removal  of  brain  and  spinal  cord  and  heart,  there  is  spon- 
taneous and  active  movement  in  wsophagus  and  stom- 
ach.i*  This  will  no  doubt  be  referred  to  the  agency  of 
the  ganglionic  plexus ;  but  similar  movements  have  been 
observed  by  Engelmann  in  the  ureter,  and  in  isolated 

after  removal  of  tlie  eye  from  the  orbit,  this  effect  was  observable  in  the 
eel.  Yet  a  very  few  days  after  extirpation  of  the  eye  the  nerves  are  dis- 
integrated. —  Proceedings  of  tlic  Loyal  Society,  1856,  p.  234. 

DoNDEES  has  the  following  observations  :  "  The  movements  of  the  iris 
are  of  two  kinds  —  reflex  and  voluntary.  Reflex  action  is  exhibited  as 
constriction  of  the  pnpil  in  con.sequence  of  the  stimulus  of  incident  light 
upon  the  retina.  Fontana  has  shown  that  the  light  falling  upon  the  iris 
produces  no  remarkable  contraction.  We  have  confirmed  this  result  by 
causing  the  image  of  a  small  distant  light  to  fall,  by  means  of  a  convex 
lens,  upon  the  iiis,  whereby,  during  slight  fierception  of  light,  a  doubtful 
contraction  occurred,  which  gave  way  to  a  strong  contraction  so  soon  as 
the  light  entering  the  pupil  excited  a  vivid  perception.  Nevertheless,  the 
experiments  of  Harless  and  Budge  have  shown  that  even  after  death,  so 
long  as  irritability  remains,  the  pupil  still  contracts  upon  the  continued 
action  of  light.  Of  the  con-ectness  of  this  we  have  satisfied  ourselves. 
In  a  dog  killed  by  loss  of  blood  the  one  ej'e  was  closed,  the  other  opened 
and  turned  to  the  light  :  after  the  lap.se  of  an  hour,  the  pupil  of  the 
opened  eye  was  perceptibly  smaller  than  that  of  the  closed  eye.  The  lat- 
ter now  remained  also  exposed  to  the  light,  and  on  the  following  day  the 
diameter  of  both  eyes  was  equal.  The  upper  jaw,  alone  with  the  eyes, 
was  taken  out  of  some  frogs  ;  one  eye  was  exposed  to  the  light,  while  the 
other  was  covered  with  a  closely  folded  piece  of  black  paper :  after 
the  lapse  of  half  an  hour  the  pupil  turned  to  the  light  was  narrow,  the 
other  wide.  But  the  latter  also  contracted  almost  immediately  after  the 
removal  of  the  pajx-r."  —  Dc^xdrhs,  On  the  Ano7nalics  of  j4 ccommodation 
end  Refraction  of  the  Eye.     Trans,  of  the  New  Sydenham  Society,  p.  572. 

*  The  experiment  often  fails,  but  I  have  seen  it  several  times  succeed. 

t  Pfliigcr's  Archil;  1872,  p.  618. 


THE  NERVOUS  MECHANISM.  231 

fragments  of  the  ureter  in  which  not  a  ganglionic  cell 
was  present.* 

92.  That  nerves  are  stimulated  by  internal  changes 
has  long  been  recognized  with  reference  to  "subjective 
sensations."  The  divided  nerve,  in  that  portion  which 
remains  connected  with  the  centre,  will  at  times  cause 
great  pain.  Obscure  organic  conditions,  changes  of  tem- 
perature, states  of  the  blood,  excite  the  nerves,  and  the 
patient  feels  as  if  the  surface  of  the  amputated  limb  were 
irritated.  It  is  all  very  well  to  call  these  "subjective 
sensations";  that  does  not  alter  the  fact  of  the  nerve 
being  called  into  activity  by  other  than  the  normal  stim- 
uli from  the  surface ;  in  like  manner  muscular  move- 
ments (which  are  not  to  be  explained  as  "subjective 
movements ")  will  be  excited  by  organic  stimuli  when 
motor-nerves  are  separated  from  their  centres.  In  each 
case  it  has  sufficed  that  the  nerve  should  be  excited ;  and 
when  excited,  no  matter  by  what  means,  the  effect  is 
always  similar. 

93.  Here  are  a  few  facts.  Stimulation  of  the  nerves 
which  send  filaments  to  the  chromatophores  of  the  skin 
in  reptiles  causes  the  skin  to  become  paler,  and  even 
colorless :  the  color-specks  disappear  under  this  contrac- 
tile stimulus.  This  being  known,  Goltz  deprived  a  frog 
of  brain,  spinal  cord,  and  heart,  thus  eliminating  all  possi- 
Ide  influence  from  them,  slit  up  the  skin  of  the  back,  and 
displayed  the  nerves  which  pass  from  each  side  of  the 
spine  to  the  skin ;  these  nerves  he  then  divided  on  the 
right  side,  and  observed  the  skin  on  this  side  slowly 
become  paler  and  paler,  till  finally  it  was  as  yellow  as 
wax ;  the  left  side,  having  its  nerves  intact,  retained  its 
color.  Two  conclusions  seemed  to  him  warranted  by  this 
experiment :  First,  that  even  in  the  dead  frog  the  nerves 
separated  from  their  centre  were  still  active ;   secondly, 

*  See  his  Eesearclies  in  Pflilr/cr's  Archiv,  Bdc.  II.  and  IV.  , 


232  THE  PHYSICAL  basis  of  mind. 

that  the  irritation  of  the  nerves  resulting  from  tlieir  sec- 
tion Mas  the  cause  of  the  color-specks  disappearing.  This 
second  conclusion  was  strengthened  wlien  he  found  that 
the  irritation  was  increased  wlien  he  cut  the  nerves  bit  by 
bit. 

It  is  not  at  present,  I  believe,  clearly  made  out  that  the 
color-specks  of  the  Cephalopoda  are  in  direct  connection 
with  nerves ;  but  it  is  tolerably  certain  tliat  they  are  in 
some  way  under  the  influence  of  nervous  stimulation, 
directly  or  indirectly.  D'Orbigny,  indeed,  goes  so  far  as 
to  say  they  are  dependent  on  the  will  of  the  animal.* 
This  seems  very  lax  language ;  but  restricting  ourselves 
to  the  fact  of  nervous  influence,  the  experiments  of  Goltz 
receive  further  illustration  in  an  observation  I  have  else- 
where recorded.-j-  I  found  that  a  strip  of  skin  taken 
from  the  dead  body  of  a  calamary  {Lolirjo)  showed  the 
color-specks  expanding  and  contracting  with  vigor. 

94.  The  heart  is  M'ell  known  to  beat  after  death,  if 
death  be  not  the  result  of  a  gradual  decay.  Sometimes, 
indeed,  its  muscular  irritability  is  so  active  that  the  heart 
will  beat  for  hours.  E.  Rousseau  observed  it  beating  in 
a  woman  twenty-seven  hours  after  she  had  been  guillo- 
tined. \  Xot  only  will  it  beat  after  death,  but  in  many 
animals  even  after  removal  from  the  body  :  the  heart  of  a 
young  puppy,  or  kitten,  will  beat  for  three  or  four  hours 
after  its  removal ;  that  of  a  full-grown  dog,  or  cat,  not  one 
hour ;  whereas  the  beating  of  that  of  a  tortoise,  or  a  frog, 
will,  under  proper  precautions,  be  preserved  for  days  — 
and  even  after  it  has  stopped,  it  may  be  stimulated  to 
fresh  pulsations. 

Physiologists  explain  this  spontaneous  movement  of 
the  heart  as  due  to  the  ganglia  in  its  substance.     This 

*  D'Orbigxt,  Dr^  Mollusques  Vivants  ct  fossils,  p.  113. 

t  Seaside  Studies,  2d  ed.,  p.  101. 

:J:  Cited  by  Buowx  SIvQUArd,  Journal  de  la  Fhi/siologie,  1858,  p.  359. 


THE  NERVOUS  MECHANISM.  233 

explanation,  which  is  founded  on  what  I  cannot  but  re- 
gard as  a  purely  imaginary  view  of  the  functions  of  gan- 
glionic cells,  must  stand  or  fall  with  that  hypothesis.  A 
long  and  arduous  investigation  has  led  me  to  doubt 
whether  in  any  case  the  heart's  movements  are  primarily 
due  to  its  ganglia ;  at  all  events,  the  same  spontaneous 
movements  are  observed  in  the  hearts  of  molluscs  and 
crustaceans,  which  are  without  even  a  trace  of  ganglia ; 
and  in  the  hearts  of  mammalian  embryos  long  before 
ganglia  or  nerve-fibres  make  their  appearance.  Not  less 
certain  is  it  that  movements  of  contraction  and  dilatation 
are  produced  in  the  blood-vessels  independently  of  all 
central  influence.  This  has  been  decisively  proved  by 
the  Italian  physiologist,  Mosso,  when  experimenting  on  an 
organ  isolated  from  the  organism ;  and  although  the  ves- 
sels have  their  nerve  cells  and  fibres,  he  justly  doubts 
whether  it  is  to  these  that  the  stimulation  is  due,  because 
the  phenomena  are  observed  after  the  nervous  vitality  has 
disappeared.  Goltz  severed  all  the  tissues  in  the  leg  of  a 
rabbit,  so  that  the  only  connection  of  the  leg  with  the 
rest  of  the  body  was  through  the  crural  vein  and  artery, 
which  kept  up  the  circulation ;  yet  although  the  nerves 
of  the  skin  were  thus  separated  from  their  centre,  so  that 
no  sensation  could  be  produced  by  stimulating  the  skin 
of  the  leg,  consequently  no  reflex  from  the  centre  on  the 
vessels,  Goltz  found  that  a  marked  reddening  of  the  skin 
from  congestion  of  the  capillaries  followed  the  application 
of  mustard  to  the  skin.  Physiologists  who  believe  that 
the  constriction  and  dilatation  of  blood-vessels  are  due  to 
the  action  of  the  ganglionic  cells  distributed  over  the 
walls  of  the  vessels  will  explain  Goltz's  observation  as  a 
case  of  reflex  action  ;  but  those  who  agree  with  me  that 
such  an  hypothesis  respecting  the  part  played  by  the  cells 
is  untenable,  will  class  the  observation  among  other  cases 
of  direct  stimulation. 


234  THE   PHYSICAL   BASIS   OF   MIND. 

95.  But  piissiug  from  these  perhaps  questionable  cases, 
let  us  glance  at  other  cases.  The  mobile  iris  of  the  bird 
displays  movements  after  the  nerves  have  been  divided. 
Even  the  voluntary  striped  muscles  are  not  altogether 
motionless.  Schiff  divided  the  hypoglossus  on  one  side, 
and  Ibund,  of  course,  the  tongue  paralyzed  on  that  side  ; 
but  lie  also  found  that  on  the  third  day  after  the  opera- 
tion some  of  the  muscles  of  that  side  were  quivering  :  the 
agitation  spread  to  others,  till  by  the  end  of  the  fourth 
(Jay  all  the  fibres  were  rhythmically  contracting.  From 
this  time  onwards,  the  contractions  were  incessant  ; 
though  they  were  never  able  to  move  the  tongue,  be- 
cause the  fibres  did  not  contract  simultaneously. 

Schiff  also  observed  that  the  hairs  over  the  eyes  and  the 
"  whiskers "  of  cats,  rabbits,  and  guinea  pigs  were  for 
months  after  section  of  their  nerves  in  incessant  rhyth- 
mical vibration.  This  was  observed  when  the  animals 
were  asleep  as  when  awake.  Valentin  records  the  spon- 
taneous movements  in  the  diaphragm  of  animals  just 
killed ;  and  this  even  after  section  of  the  phrenic  nerve. 
The  same  movements  may  be  seen  in  the  operculum  of 
fishes.  Henle  observed  the  spontaneous  contractions  of 
the  intercostal  muscles ;  which  Schiff  confirms,  adding 
that  the  movements  observed  by  him  in  cats  and  birds 
were  not  simply  contractions  of  some  fibres,  but  of  all  the 
muscles,  so  that  three  or  four  excised  ribs  rhythmically 
contracted  and  expanded. 

I  have  performed  a  great  many  experiments  with  a 
view  of  determining  this  question,  but  the  phenomena 
were  so  variable  that  I  refrain  from  adducing  any,*  and 

*  Dr.  NoRRis  has  recorded  some  striking  observations  in  liis  paper  on 
"Muscular  Irritability  "  in  the  Journal  of  Anatonvi,  1867,  No.  II.  p. 
217.  Here  is  the  only  one  I  can  find  room  for  :  "  On  taking  up  the  dead 
frog  and  touching  the  limb  (which  during  life  had  been  paralyzed  by  sec- 
tion of  its  nerve)  with  my  finger,  it  was  suddenly  shot  out  as  if  alive.  I 
placed  the  body  down,  and  one  or  two  apimrcntly  spontaneous  movements 


S9 


THE  NERVOUS  MECHANISM.  235 

merely  state  the  general  result  as  one  in  harmony  with 
the  foregoing  examples.  The  great  variability  of  the  phe- 
nomena depends  upon  the  variable  conditions  of  muscular 
irritability  and  anatomical  relations.  When  the  heart  of 
one  woman  is  found  beating  twenty-seven  hours  after 
death,  while  in  most  men  and  women  it  ceases  after  a 
few  minutes,  we  must  be  prepared  to  find  different,  and 
even  contradictory  phenomena  under  varying  unkno\^»  ^J 
conditions.  There  is,  however,  a  general  agreement  amoi§  Hj 
experimenters  that  muscular  irritability  increases  aft^  W 
separation  fi^om  nerve-centres,  and  then  quickly  decreas^  ^ 
again.  M  p^ 

96.   Although  the  stimulation  of  muscles  usually  comS    S||{ 
throvgh  a  nerve-centre,  yet  since  the  muscles  do  not  d™    ► 
rive  their  Contractility  from  nerve-centres  any  stimulfV    ET 
tion  will  suffice.     Now  since  we  have  abundant  procfi  c^ 
that   sensory  nerves  are   stimulated   by  certain   organfe  ^ 
changes,  by  poisons  in  the  blood,  excess  of  carbonic  acid,    q 
etc.,  we  are   justified  in  concluding  that  motor  nerves  Jp* 
will  be  stimulated  in   like   maimer,  and  thus  muscular 
movement  be  produced  occasionally  without  the  inter- 
vention of  a  centre.     Pressure  on  a  motor  nerve,  or  the 
irritation  which  results  from  inflammation,  will  determine 
contraction,   or   secretion   directly.     Eecently,   Erb   and 
Wcstphal  have  disclosed  the  fact  that  the  leg  will  be 
suddenly  jerked  out  if  the  patella  be  gently  tapped ;  and 
they  prove  this  not  to  be  a  reflex  action,  because  it  fol- 
lows with  the  same  certainty  after  the  skin  has  been 
made  insensible.* 

There   are   doubtless   many  other   phenomena  which, 
though   commonly   assigned    to    reflex    stimulation,   are 

of  small  extent  afterwards  occurred.  On  touching  tlie  skin  gently  with 
the  point  of  a  needle,  by  the  .slight  pressure  upon  the  muscle  beneath, 
movements  of  the  lirnh  were,  also  induced,  hut  this  high  degree  of  exalta- 
tion very  rapidly  disa[ipeared." 

*  See  their  papers  in  the  Archie  fiir  PsycJdatrk,  1875,  Bd.  V.  Heft  3. 


236  THE  PHYSICAL  BASIS   OF  MIND. 

really  due  to  direct  stimulation.  Eesearcli  might  profit- 
ably be  turned  towards  the  elucidation  of  this  point. 
Since  there  is  demonstrable  evidence  that  a  nerve  when 
no  longer  in  connection  with  its  centre,  or  with  ganglionic 
cells,  may  be  excited  by  electricity,  pressure,  thermal  and 
chemical  stimuli,  we  must  conclude  that  even  when  it  is 
in  connection  with  its  centre,  any  local  irritation  from 
pressure,  changes  in  the  circulation,  etc.,  will  also  excite 
it.  But  as  such  local  excitations  will  have  only  local  and 
isolated  effects,  they  will  rarely  be  conspicuous. 


THE  NEEVOUS  MECHANISM.  237 


CHAPTER  VI. 

WHAT   IS   TAUGHT   BY   EMBRYOLOGY? 

97.  Subject  to  the  qualification  expressed  in  the  last 
chapter,  stimulation  of  muscles  and  glands  involves  a 
neural  process  in  ingoing  nerve,  centre,  and  outgoing 
nerve.  These  are  the  triple  elements  of  the  "  nervous 
arc."  If  muscles  were  directly  exposed  to  external  in- 
lluences,  they  would  be  stimulated  without  the  interven- 
tion of  a  centre;  but  as  a  matter  of  fact  they  never  are 
thus  exposed,  being  always  protected  by  the  skin.  Did 
the  skin-nerves  pass  directly  to  the  muscles  underneath, 
they  would  move  those  muscles,  without  the  intervention 
of  a  centre ;  but  as  a  matter  of  fact  the  skin-nerves  pass 
directly  to  a  centre,  so  that  it  is  only  through  a  centre 
that  they  can  act  upon  the  muscles.  Were  muscles  and 
glands  directly  connected  with  sensitive  surfaces,  their 
activity  would  indeed  be  awakened  by  direct  stimulation; 
l)ut  unless  the  muscles  were  so  connected  the  one  with 
the  other,  by  anastomosis  of  fibres  or  continuity  of  tissue, 
that  the  movement  of  one  was  the  movement  of  all,  there 
would  need  to  be  some  other  channel  by  which  their  sep- 
arate energies  should  be  combined  and  co-ordinated.  In 
the  higher  organisms  anastomosis  of  muscles  is  rare,  and 
the  combination  is  effected  by  means  of  the  nerves. 

98.  Although  analysis  distinguishes  the  two  elements 
of  the  neuro-muscular  system,  assigning  separate  prop- 
erties to  the  separate  tissues,  an  interpretation  of  the  phe- 
nomena demands  a  synthesis,  so  that  a  movement  is  to  be 


238  THE   niYSICAL   BASIS   OF   MIND. 

conceived  as  always  involving  Sensibility,  and  a  sensation 
as  always  involving  Motility.*  In  like  manner,  although 
analysis  distinguishes  the  various  organs  of  the  body, 
assigning  separate  functions  to  each,  our  interpretation 
demands  their  synthesis  into  an  organism ;  and  we  have 
thus  to  explain  how  the  vjhole  has  different  j^^o^^s,  and 
how  these  difierent  parts  are  brought  into  unity.  Embry- 
ology helps  us  to  complete  the  fragmentary  indications  of 
Anatomy  and  Physiology. 

99.  Take  a  newly  laid  egg,  weigh  it  carefully,  then 
hatch  it,  and  when  the  chick  emerges,  weigh  both  chick 
and  shell :  you  will  find  that  there  has  been  no  increase 
of  weight.  The  semifluid  contents  have  become  trans- 
formed into  bones,  muscles,  nerves,  tendons,  feathers,  beak, 
and  claws,  all  without  increase  of  substance.  There  has 
been  differentiation  of  structure,  nothing  else.  Oxygen 
has  passed  into  it  from  without ;  carbonic  acid  has  passed 
out  of  it.  The  molecular  agitation  of  heat  has  been  re- 
quired for  the  rearrangements  of  the  substance.  With- 
out oxygen  there  would  have  been  no  development. 
Without  heat  there  would  have  been  none.  Had  the 
shell  been  varnished,  so  as  to  prevent  the  due  exchange 
of  oxygen  and  carbonic  acid,  no  chick  would  have  been 
evolved.  Had  only  one  part  of  the  shell  been  varnished, 
the  embryo  would  have  been  deformed. 

99 «.  The  patient  labors  of  many  observers  (how  pa- 
tient only  those  can  conceive  who  have  made  such 
observations !)  have  detected  something  of  this  wondrous 
history,  and  enabled  the  mind  to  picture  some  of  the  in- 
cessant separations  and  reunions,  chemical  and  morpho- 
logical. Each  stage  of  evolution  presents  itself  as  the 
consequence  of  a  preceding  stage,  at  once  an  emergence 
and  a  continuance ;    so  that  no  transposition  of   stages 

*  This  latter  statement  will  be  justified  when  I  come  to  expound  the 
Triple  Process,  which  I  have  named  the  Psychological  Spedrum. 


THE  NERVOUS  MECHANISM.  239 

is  possible ;  each  has  its  appointed  place  in  the  series 
(Problem  I.  §  107).  For  in  truth  each  stage  is  a  ^9?'o- 
cess  —  the  sum  of  a  variety  of  co-operant  conditions.  We, 
lookincr  forward,  can  foresee  in  each  what  it  will  become, 
as  we  foresee  the  man  in  the  lineaments  of  the  infant; 
but  in  this  prevision  we  always  presuppose  that  the 
regular  course  of  development  will  proceed  unchecked 
through  the  regular  succession  of  special  conditions :  the 
infant  becomes  a  man  only  when  this  succession  is  unin- 
terrupted. Obvious  as  this  seems,  it  is  often  disregarded ; 
and  the  old  metaphysical  conception  of  potential  powers 
obscures  the  real  significance  of  Epigenesis.  The  poten- 
tiality of  the  cells  of  the  germinal  membrane  is  simply 
their  capability  of  reaching  successive  stages  of  develop- 
ment under  a  definite  series  of  co-operant  conditions. 
We  foresee  the  result,  and  personify  our  prevision.  But 
that  result  wdll  not  take  place  unless  all  the  precise 
changes  that  are  needful  serially  precede  it.  A  slight 
pressure  in  one  direction,  insufficient  to  alter  the  chemi- 
cal composition  of  the  tissue,  may  so  alter  its  structure 
as  to  disturb  the  regular  succession  of  forms  necessary  to 
the  perfect  evolution. 

100.  The  egg  is  at  first  a  microscopic  cell,  the  nucleus 
of  which  divides  and  subdivides  as  it  gro\\s.  The  egg 
becomes  a  hollow  sphere,  the  boundary  wall  of  which  is 
a  single  layer  of  cells,  all  so  similar  that  to  any  means 
of  appreciation  we  now  possess  they  are  indistinguishable. 
They  are  all  the  progeny  of  the  original  nucleus  and 
yolk,  or  cell  contents.  Very  soon,  however,  they  begin 
to  show  distinguishable  differences,  not  perhaps  in  Jdnd, 
but  in  (hrjrce.  The  wall  of  this  hollow  spliore  is  rapidly 
converted  into  tlie  germinal  membrane,  out  of  which  the 
embryo  is  i'ormed.  Kowalewsky  (confirmed  l)y  ]>alfour) 
has  pointed  out  how  in  the  Amphioxus  the  liollow  si)here 
first  assumes  an  oval  shape,  and  then,  by  an  indentation 


240  TIIK    PHYSICAL    BASIS    OF    MIND. 

(if  the  under  side,  with  corresponding  curvature  of  the 
upper  side,  presents  somewhat  the  shape  of  a  bowl.  The 
curvature  increases,  and  the  curved  ends  approaching 
each  other,  the  original  cavity  is  reduced  to  a  thin  line 
separating  the  upper  from  the  under  surface.  The  cavity 
of  the  body  is  formed  by  the  curving  downwards  of  this 
double  layer  of  the  germinal  membrane. 

101.  This  is  not  precisely  the  course  observable  in 
other  vertebrates ;  but  in  all,  the  germinal  membrane, 
which  lies  like  a  watch-glass  on  the  surface  of  the  yolk, 
is  recognizable  as  two  distinct  layers  of  very  similar  cells. 
What  do  these  represent  ?  They  are  the  starting-points 
of  the  two  great  systems :  Instrumental  and  Alimental. 
The  one  yields  the  dermal  surface ;  the  other  the  mucous 
membrane.  Each  follows  an  independent  though  analo- 
gous career.  The  yolk  furnishes  nutrient  material  to  the 
germinal  membrane,  and  so  passes  more  or  less  directly 
into  the  tissues;  but  unlike  the  germinal  membrane,  it 
is  not  itself  to  any  great  extent,  the  seat  of  generation  by 
segmentation.  There  are  two  yolks :  the  yellow  and 
the  white  (which  must  not  be  confounded  with  what  is 
called  the  white  of  egg) ;  and  their  disposition  may  be 
seen  in  the  diagram  (Fig.  14)  copied  from  Foster  and  Bal- 
four's work.  The  importance  of  the  white  yolk  is  that 
it  passes  insensibly  into  a  distinct  layer  of  the  germinal 
membrane,  between  the  two  primary  layers.*  Each  of 
the  three  layers  of  the  germinal  membrane  has  its  specific 
character  assigned  to  it  by  embryologists,  who,  however, 
are  not  all  in  agreement.  Some  authorities  regard  the 
topmost  layer  as  the  origin  of  the  nervous  system,  the 
epidermis,  with  hair,  feathers,  nails,  horns,  the  cornea  and 
lens  of  the  eye,  etc.    To  the  middle  layer  are  assigned  the 

*  Foster  and  Balfour,  Elements  of  Embryoloriy,  1874,  Part  I.  p.  52. 
His,  Untersuchungen  uber  die  erste  Aiilage  dcs  Wirbelthierleibes,  1868, 
p.  197. 


THE   NERVOUS   MECHANISM. 


241 


muscular  and  osseous  systems,  the  sexual  organs,  etc.  To 
the  innermost  layer,  the  alimentary  canal,  with  liver,  pan- 
creas, gastric  and  enteric  glands.  Other  authorities  are 
in  favor  of  two  primary  layers :   one  for  the   nervous. 


e^.i 


Fig.  14.  —  Diagrammatic  section  of  an  unincubated  hen's  egg.  bl,  blastoderm  ;  w  y, 
white  yolk  ;  y  y,  yellow  yolk  ;  v  t,  vitelline  membrane  ;  x  and  w,  layers  of  albumen  ; 
ch  I,  chalaza  ;  a  ch,  air-chamber ;  i  s  m,  internal  layer  of  shell  membrane  ;  s  m,  ex- 
ternal layer  ;  s,  shell. 


muscular,  osseous,  and  dermal  systems ;  the  other  for  the 
viscera  and  unstviped  muscles.  Between  these  two  layers, 
a  third  gradually  forms,  w^hich  is  specially  characterized 
as  the  vascular. 

102.  INfessrs.  Foster  and  Balfour,  avoiding  the  con- 
troverted designations  of  serous,  vascular,  and  mucous 
layers,  or  of  sensorial,  motor  germinative,  and  glandular 
layers,  employ  designations  whicli  are  independent  of 
theoretic  interpretation,  and  simply  describe  the  position 
of  the  layers,  namely,  cpiUast  for  the  upper,  mcsohlast  for 
the  middle,  and  hypoblast  for  the  under  layer.  From  the 
VOL.  iir.  11  p 


242  THE   PHYSICAL   BASIS   OF   MIND. 

epiblust  they  derive  the  epidermis  and  central  nervous 
system  (or  would  even  limit  the  latter  to  the  central  gray 
mutter),  together  with  some  parts  of  the  sense-organs. 
From  the  mesoblast,  the  muscles,  nerves  (and  probably 
white  matter  of  the  centres),  bones,  connective  tissue, 
and  blood-vessels.  From  the  hypoblast,  the  epithelial 
lining  of  tlie  alimentary  canal,  trachea,  bronchial  tubes, 
as  well  as  the  liver,  pancreas,  etc.*  Kollikcr's  suggestion 
is  much  to  the  same  effect,  namely,  that  the  three  layers 
may  be  viewed  as  two  epithelial  layers,  between  which 
subsequently  arises  a  third,  the  origin  of  nerves,  muscles, 
bones,  connective  tissue,  and  vessels.^ 

103.  The  way  in  which  the  history  may  be  epitomized 
is  briefly  this :  There  are  two  germinal  membranes,  re- 
spectively representing  the  Instrumental  and  Alimental 
Systems.  Each  membrane  differentiates,  by  different  ap- 
propriations of  the  yolk  substance,  into  three  primary 
layers,  cjnthdial,  neural,  and  muscular.  In  the  e])iblast, 
or  upper  membrane,  these  layers  represent :  1°,  the  future 
epidermis  with  its  derivatives  —  hair,  feathers,  nails,  skin 
glands,  and  chromatophores ;  2°,  the  future  nervous  tis- 
sue ;  o°,  the  future  muscular  tissue. J  (Bone,  dermis, 
connective  tissue,  and  blood-corpuscles  are  subsequent 
formations.) 

Tlie  hypoblast,  or  under  membrane,  in  an  inverted 
order  presents  a  similar  arrangement :  1°,  the  unstriped 

*  They  state  that  the  cells  of  the  epiblast  are  the  results  of  direct 
.segmentation,  whereas  the  cells  of  the  other  layers  are  formed  at  a  sub- 
sequent period,  and  are  only  indirectly  results  of  segmentation.  But  if 
the  observations  of  Kowalewsky  are  exact,  this  is  not  the  case  with  the 
hypoblast  of  the  Amphioxus,  which  is  from  the  first  identical  with  the 
epiblast. 

t  KoLLiKER,  Entvxicklwngsgeschichte  des  Menschen  und  dcr  hiiheren 
Thicrc,  1861,  p.  71. 

t  [According  to  Balfour's  recent  observations,  a  large  part  of  the 
muscular  tissue  is  derived  from  the  layer  of  the  mesoblast  belonging  to 
the  hypoblast.] 


THE  NERVOUS  MECHANISM.  243 

muscular  tissue  of  viscera  and  vessels ;  2°,  the  nervous 
tissue  of  the  sympathetic  system;  3°,  the  epithelial  lin- 
ing of  the  alimentary  canal  with  its  glands. 

Fundamentally  alike  as  these  two  membranes  are,  they 
have  specific  differences;  but  in  both  we  may  represent 
to  ourselves  the  cmhryological  unit  constituted  by  an  epi- 
thelial cell,  a  nerve-cell,  and  a  muscle-cell.  All  the  other 
cells  and  tissues  are  adjuncts,  necessary,  indeed,  to  the 
working  of  the  vital  mechanism,  but  subordinated  to  the 
higher  organites. 

104.  This  conception  may  be  compared  with  that  of  ^ 
His  in  the  division  of  Archiblast  and  Parablast  assigned 
by  him  to  the  germ  and  accessory  germ.*  We  can  im- 
agine, he  says,  the  whole  of  the  connective  substances 
removed  from  the  organism,  and  thus  leave  behind  a 
scaffolding  in  which  brain  and  spinal  cord  would  be  the 
axis,  surrounded  by  muscles,  glands,  and  epithelium,  and 
nerves  as  connecting  threads.  All  these  parts  stand 
in  more  or  less  direct  relation  to  the  nervous  system. 
All  are  continuous.  By  a  similar  abstraction  we  can 
imagine  this  organic  system  removed,  and  leave  behind 
the  connected  scaffolding  which  is  formed  from  the 
accessory  germ ;  but  this  latter  has  only  mechanical 
significance ;  the  truly  vital  functions  belong  to  the  other 
system. 

105.  The  researches  of  modern  histologists  have  all 
converged  towards  the  conclusion  that  the  organs  of 
Sense  are  modifications  of  the  surface,  with  epithelial 
cells  which  on  the  one  side  are  connected  Avith  termi- 
nal hairs,  or  other  elements  adapted  to  the  reception  of 
stimuli,  and  are  connected  on  the  other  side  through 
nerve-fibres  with  the  perceptive  centres.  It  has  been 
shown  that  nerve-filjres  often  terminate  in  (or  among) 
epithelial  cells  —  sensory  fibres  at  the  surface,  and  motor- 

*  His,  Untersuchungcn,  pp.  39,  40. 


244  THE   PHYSICAL  BASIS   OF  MIND. 

fibres  in  the  glands.*  Whether  the  fibres  actually  pene- 
trate tlie  substance  of  the  cell,  or  not,  is  still  disputed. 
Enough  for  our  present  purpose  to  understand  that  there 
is  a  i^hysiolofjical  connection  between  the  two,  and  above 
all  tliat  sensory  nerves  are  normally  stimulated  through 
some  epithelial  structure  or  other. 

106.  And  this  becomes  clear  when  we  go  back  to  the 
earliest  indications  of  development.  Look  at  Fig.  15,  rep- 
resenting a  transverse  section  of  the  germinal  membranes 
in  a  chick  after  eishteen  hours'  incubation.      Here  the 


Fig.  15.  —  Transverse  section  of  a  Blastoderm  Incubated  for  eighteen  hours.  The  sec- 
tion passes  through  the  medullary  groove,  m  e.  A,  epiblast.  B,  mesoblast.  C,  hy- 
poblast,   mf,  medullary  fold  ;  c  h,  notochord. 


three  layers,  A,  B,  and  C,  have  the  aspect  of  simple  cells 
very  slightly  differing  among  each  other.  Yet  since  each 
layer  has  ultimately  a  progeny  which  is  characteristically 
distinguishable,  we  may  speak  of  each  not  as  what  it  now 
is,  but  what  it  will  become.     Although  the  most  expert 

*  Quite  recently  Owsjanxikow  has  pointed  out  the  termination  of 
fibres  in  the  phosphorescent  cells  of  the  Lampyris  Noctiluca.  See 
his  paper  in  the  Memoires  de  I'Jcad.  de  St.  Petersbourg,  1868,  XI.  17. 
These  phosphorescent  cells  are  said  to  be  ganglion-cells  by  Panceri, 
Intorao  delta,  luce  che  emana.  dalle  celleule  nervosc  (Rendiconto  della 
Accad.  delle  Scienze,  April,  1872);  and  by  Eimer,  Archiv  fur  mikros. 
A'lmtomie,  1872,  p.  653.  Kolliker  also  calls  the  phosphorescent  organ 
a  nervous  organ.  This  is  not  to  be  intei-preted  as  meaning  that  neu- 
rility  is  phosphorescence,  but  simply  that  in  some  nerve-cells  there  is 
jjhosphorescent  matter,  which  is  called  into  activity  by  stimidus  of  the 


THE  NERVOUS  MECHANISM.  245 

embryologist  is  often  unable  to  distinguish  the  embryo  of 
a  reptile  from  that  of  a  bird  or  of  a  mammal,  at  certain 
stages  of  evolution,  so  closely  does  the  one  resemble  tlie 
other,  yet  inasmuch  as  the  embryo  of  a  reptile  does  not, 
cannot  become  a  bird,  nor  that  of  a  bird  a  mammal,  he  is 
justified  in  looking  forward  to  what  each  will  become,  and 
in  calling  each  embryo  by  its  future  name.  On  the  same 
ground,  although  we  cannot  point  to  any  such  distinction 
between  the  layers  of  the  blastoderm  as  I  have  indicated 
in  the  separation  of  Instrumental  and  Alimental  Systems, 
nor  specify  any  characters  by  which  the  cells  can  be  rec- 
ognized as  epithelial,  neural,  and  muscular,  yet  a  forward 
glance  prefigures  these  divisions.  We  know  that  the  first 
result  of  the  segmentation  of  the  yolk  is  the  formation 
of  cells  all  alike,  which  in  turn  grow  and  subdivide  into 
other  cells.  We  know^  that  these  cells  become  variously 
modified  both  in  composition  and  structure,  and  that  by 
such  differentiations  the  simple  organism  becomes  a  com- 
plex of  organs. 

107.  But  here  it  is  needful  to  recall  a  consideration 
sometimes  disregarded,  especially  by  those  who  speak  of 
Differentiation  as  if  it  were  some  magical  Formative  Prin- 
ciple, quite  independent  of  the  state  of  the  organized 
substance  which  is  formed.  There  is  a  luminous  concep- 
tion —  first  announced  by  Goethe,  and  subsequently  de- 
veloped by  Milne  Edwards  —  which  regards  the  organism 
as  increasing  in  power  and  complexity  by  a  physiological 
"  division  of  labor,"  very  similar  to  that  division  of  em- 
ployments whicli  characterizes  the  developed  social  organ- 
ism. But  tlie  meta])hor  has  sometimes  been  misleading; 
it  has  been  interpreted  as  indicating  that  Function  cn^ates 
Organ  (see  Problem  I.  §  88),  and  as  if  Difrercntiation 
itself  were  something  more  than  the  expression  ol'  the 
changes  resulting  from  the  introduction  of  different  ele- 
ments.    In  the  Social  Organism  a  "division  of  labor" 


2-46  THE  PHYSICAL  basis  of  mind. 

presupposes  that  laborers  with  their  labor-materials  are 
already  existing ;  the  change  is  one  of  rearrangement : 
instead  of  each  laborer  employing  his  skill  in  doing  many 
kinds  of  work,  lie  restricts  it  to  one  kind,  which  he  is 
then  able  to  do  with  less  loss  of  time  and  power.  Thus 
is  social  power  multiplied  without  increase  of  population, 
and  the  social  organism  becomes  more  complex  by  the 
differentiation  of  its  organs.  It  is  not  precisely  thus  with 
the  Animal  Organism  during  its  evolution.  Indeed  to 
suppose  that  the  differentiation  of  the  germinal  membrane 
into  special  tissues  and  organs  takes  place  by  any  such 
division  of  employments,  is  to  fall  into  the  ancient  error 
of  assuming  the  organism  to  exist  preformed  in  the  ovum. 
The  unequivocal  teaching  of  Epigenesis  is  that  each  part 
is  produced  out  of  the  elements  furnished  by  previous 
parts  ;  and  for  every  differentiation  there  must  be  a  differ- 
ence in  composition,  structure,  or  texture  —  the  first  con- 
dition being  more  important  than  the  second,  the  second 
more  important  than  the  third.  The  word  protoplasm  has 
almost  as  wide  a  generality  as  the  word  animal,  and  is 
often  used  in  forgetfulness  of  its  specific  values  :  the  pro- 
toplasm of  a  nerve-cell  is  not  the  same  as  that  of  a  blood- 
cell,  a  muscle-cell,  or  a  connective-tissue  cell,  any  more 
than  a  bee  is  a  butterfly,  or  a  prawn  a  lobster.  No  sooner 
has  the  specific  character  been  acquired,  no  sooner  is  one 
organite  formed  by  differentiation,  than  there  is  an  abso- 
lute barrier  against  any  transformation  of  it  into  any  other 
kind  of  organite.  The  nerve-cell,  muscle-cell,  and  epi- 
thelial cell  have  a  common  starting-point,  and  a  commu- 
nity of  substance ;  but  the  one  can  no  more  be  trans- 
formed into  the  other  than  a  mollusc  can  be  transformed 
into  a  crustacean.  In  the  homogeneous  cellular  mass 
which  subsequently  becomes  the  "vertebral  plates,"  a 
group  of  cells  is  very  early  differentiated :  this  is  the 
rudimentary  spinal  ganglion,  which  becomes  enveloped  in 


THE  NERVOUS  MECHANISM.  247 

a  membrane,  and  then  pursues  a  widely  different  course 
from  that  of  the  other  ceils  surrounding  it,  so  that  "  the 
same  cell  which  was  formerly  an  element  of  the  vertebral 
plate  now  becomes  a  nerve-cell,  while  its  neighbors  be- 
come cartilage-cells."  *  Indeed  all  the  hypotheses  of  trans- 
formation of  tissues  by  means  of  Differentiation  are  as 
unscientific  as  the  hypotheses  of  the  transformation  of 
animals.  In  the  organism,  as  in  the  Cosmos,  typical  forms 
once  attained  are  retained.  There  probably  was  a  time  in 
the  history  of  the  animal  series  when  masses  of  proto- 
plasm by  appropriating  different  materials  from  the  sur- 
rounding medium  were  differentiated  into  organisms  more 
complex  and  more  powerful  than  any  which  existed  be- 
fore. But  it  is  obvious  that  from  a  common  starting-point 
there  could  have  been  no  variations  in  development  with- 
out the  introduction  of  new  elements  of  composition: 
there  might  have  been  many  modifications  of  structure, 
but  unless  these  facilitated  modifications  of  composition, 
there  could  never  have  resulted  the  striking  differences 
observed  in  animal  organisms.-f- 

108.  To  return  from  this  digression,  we  may  liken  the 
three  primary  layers  of  the  germinal  membranes  to  the 
scattered  and  slightly  different  masses  of  protoplasm  out 
of  which  the  animal  kingdom  was  developed.  In  this 
early  stage  there  are  no  individualized  organites  —  no 
nerve-cells  or  muscle-cells.  Tliey  are  cells  ready  to  re- 
ceive modifications  both  of  composition  and  structure, 
appropriating  slightly  different  elements  from  the  yolk, 
and  according  to  such  appropriation  acquiring  different 

*  Bidder  unci  Kupffer,  Tcxtur  dcs  RiiclcrMmarks,  1857,  p.  108.  [What 
is  said  in  the  text  ha.s  been  rendered  doubtful  by  the  recent  researches  of 
Mr.  F.  Balfour,  On  tJie  Development  of  the  Spinal  Nerves  in  Elasmo- 
hranch  Fishes  (Philos.  Trans.,  Vol.  CLXVI.  Part  I.),  whicli  show  that  in 
these  fishes  the  ganglion  has  its  origin  in  the  spinal  cord.] 

t  Comp.  PiiORLKM  I.  §  130,  witli  tlie  remarks  of  Cii.\rlks  Konix, 
Anatomic  et  Physiologic  Cellulaircs,  1873,  p.  20. 


248  t;ii:  thysical  basis  of  mind. 

properties.  And  lliis  is  necessarily  so,  since  tlio  different 
cells  have  not  exactly  the  same  relation  to  the  yolk,  nor 
are  they  in  exactly  the  same  relation  to  the  incident  forces 
which  determine  the  molecular  changes.  The  uppermost 
layer  (epiblast)  under  such  variations  develops  into  epithe- 
lium and  central  nerve-tissue  ;  the  epithelial  cell  cannot 
develop  into  a  nerve-cell,  the  two  organites  are  markedly 
unlike,  yet  both  spring  from  a  common  root.  Another 
modification  results  in  the  development  of  muscle-cells 
from  the  inner  layer. 

109.  Hence  we  can  understand  how  the  surface  is  sen- 
sitive even  in  organisms  that  are  without  nerve-tissue ; 
and  also  how  even  in  the  highest  organisms  there  is  an 
intimate  blending  of  epithelial  with  neural  tissues.  The 
same  indication  explains  the  existence  of  neuro-muscular 
cells  in  the  Hydra,  recorded  by  Kleinenberg,  and  of  neuro- 
muscular fibres  in  the  Bcroe,  by  Eimer.*  In  the  simpler 
organisms  the  surface  is  at  once  protective,  sensitive,  and 
absorbent.  It  shuts  off  the  animal  from  the  external 
medium,  and  thus  individualizes  it ;  at  the  same  time  it 
connects  this  individual  with  the  medium ;  for  it  is  the 
channel  through  which  the  medium  acts,  both  as  food  and 
stimulus.  The  first  morphological  change  is  one  whereby 
a  part  of  the  surface  is  bent  inwards,  and  forms  the  lining 

*  Kleinexbeeg,  Hydra;  Fine  Anatomisch-Entwickclungs-Untcrsu- 
cJmng,  1872,  p.  11.     Eimer,  Zoologische  Studien  auf  Capri,  1873,  p.  66. 

A  similar  formation  is  described  by  Dr.  Allman  in  the  Myriothda  ;  he 
says,  however,  that  he  has  never  been  able  to  trace  a  direct  continuity  of 
the  caudal  processes  of  the  cells  with  muscular  fibrils.  He  believes  that 
the  processes  make  their  way  to  the  muscular  layer  through  undifferen- 
tiated protoplasm.  —  P/i27os.  Transactions,  Vol.  CLXV.  Part  II.  p.  554. 

An  intermediate  stage  between  this  neuro-muscular  tissue  and  the  two 
differentiated  tissues  seems  presented  in  the  Nematoid  worms  which  have 
muscles  that  send  off  processes  into  which  the  nerves  pass.  Gegekbauu 
declares  his  inability  to  decide  whether  these  processes  are  muscles  or 
nerves.  BUtsciili  thinks  the  nerve-process  blends  with  the  muscle-pro- 
cess.—  Archiv  fiir 'inikros.  Analomie,  1873,  p.  89. 


THE  NERVOUS  MECHANISM.  249 

of  the  body's  cavity.  Soon  there  follows  such  a  modifi- 
cation of  structure  between  the  outer  and  inner  surfaces 
(ectoderm  and  cndodcrm)  that  the  one  is  mainly  sensitive 
and  protective,  the  other  mainly  protective  and  absorbent. 
The  outer  surface  continues  indeed  to  absorb,  but  its  part 
in  this  function  is  insignificant  compared  with  that  of  the 
inner  surface,  which  not  only  absorbs  but  secretes  fluids 
essential  to  assimilation.  The  inner  surface,  although 
sensitive,  is  subjected  to  less  various  stimulation,  and  its 
sensibility  is  more  uniform. 

110.  The  uppermost  of  the  primary  layers  we  have 
seen  to  be  epithelial ;  and  we  know  that  the  first  lines  of 
the  central  nervous  system  are  laid  there.  A  depression 
called  the  medullary  groove  is  the  first  indication  of  the 
future  cerebro-spinal  axis.  Some  writers  —  Kolliker,  for 
instance  —  regard  this  medullary  groove  as  continuous 
with  but  different  from  the  epithelial  layer;  others  main- 
tain that  it  lies  underneath  the  epithelium,  just  as  we  see 
it  in  later  stages,  when  the  differentiation  between  epi- 
thelial and  nerve  cell  has  taken  place.  Since  no  one  dis- 
putes the  fact  that  when  the  groove  becomes  a  closed 
canal  its  lining  is  epithelial,  one  of  two  conclusions  is  in- 
evitable :  either  the  cells  of  the  primary  layer  develop  in 
the  two  diverse  directions,  epithelial  and  neural ;  or  else 
epithelial  cells  can  be  developed  on  the  surface  of  neural 
cells  and  out  of  them.  The  latter  conclusion  is  one 
which,  involving  the  conception  of  transformation,  would 
seem  to  be  put  out  of  court.  I  tliink,  then,  we  must 
admit  that  the  under  side  of  the  primary  layer  of  cells 
becomes  differentiated  into  nerve-cells ;  and  this  is  in 
accordance  with  the  observations  of  Messrs.  Foster  and 
Balfour.* 

*  "The  gray  matter  of  the  cord  seems  undouljtcdly  to  lie  formed  by 
a  metamorphosis  of  the  external  cells  of  tlie  epihlast  of  the  neural  tube, 
and  is  directly  continuous  with  the  epithelium;  there  being  no  strong 
line  of  demarcation  between  them."  —  Op.  cit.,  p.  185. 
11* 


250  THE  PHYSICAL  BASIS   OF  mND. 

111.  While  there  is  this  intimate  morphological  and 
physiological  blending  of  epithelial  and  neural  organites, 
there  is  an  analogous  relation  between  neural  and  mus- 
cular organites.  As  the  neural  layer  lies  under  the  epi- 
thelial, the  muscular  lies  under  the  neural.  The  surface 
stimulation  passes  to  the  centre,  and  is  reflected  on  the 
muscles.  Embryology  thus  teaches  why  a  stimulus  from 
the  external  medium  must  be  propagated  to  a  nerve-centre 
before  it  reaches  the  muscles ;  and  why  a  stimulus  on  one 
part  of  the  surface  may  set  all  the  organism  in  movement, 
by  passing  through  a  centre  which  co-ordinates  all  move- 
ments. This,  of  course,  only  applies  to  the  higher  organ- 
isms. In  the  simpler  structures  the  sensitive  surface  is 
directly  continuous  with  the  motor  organs. 

It  is  unnecessary  here  to  pursue  this  interesting  branch 
of  our  subject ;  nor  need  we  follow  the  analogous  evolu- 
tion of  the  second  germinal  membrane  representing  the 
Alimental  System.  Our  attention  must  be  given  to  what 
is  known  and  inferred  respecting  the  elementary  structure 
of  the  nerves  and  centres,  on  which  mainly  the  interest 
of  the  psychologist  settles,  since  to  him  the  wdiole  of 
Physiology  is  merged  in  nerve  actions. 


THE  NERVOUS  MECHANISM.  251 


CHAPTER   VII. 

THE  ELEMENTARY  STRUCTURE   OF   THE   NERVOUS   SYSTEM. 

112.  The  progress  of  science  involves  an  ever-increas- 
ing Analysis.  Investigation  is  more  and  more  directed 
towards  the  separated  details  of  the  phenomena  previously 
studied  as  events ;  the  observed  facts  are  resolved  into 
their  component  factors,  complex  wholes  into  their  sim- 
pler elements,  the  organism  into  organs  and  tissues.  But 
while  the  analytical  process  is  thus  indispensable,  it  is,  as 
I  have  often  to  insist,  beset  with  an  attendant  danger, 
namely,  that  in  drawing  the  attention  away  from  one 
group  of  factors  to  fix  it  exclusively  on  another,  there  is 
a  tendency  to  forget  this  artifice,  and  instead  of  restoring 
the  factors  provisionally  left  out  of  account,  we  attempt 
a  reconstruction  in  oblivion  of  these  omitted  factors. 
Hence,  instead  of  studying  the  properties  of  a  tissue  in^ 
all  the  elements  of  that  tissue,  and  the  functions  of  an 
organ  in  the  anatomical  connections  of  that  organ,  a  single 
element  of  the  tissue  is  made  to  replace  the  whole,  and 
very  soon  the  function  of  the  organ  is  assigned  to  this 
particular  clement.  The  "superstition  of  the  nerve-cell" 
is  a  striking  illustration.  The  cell  has  usurped  the  place 
of  the  tissue,  and  has  come  to  be  credited  with  central 
functions ;  so  that  wherever  anatomists  have  detected 
ganglionic  cells,  physiologists  have  not  liesitated  to  place 
central  functions.  By  such  interpretations  the  heart  and 
intestines,  the  glands  and  blood-vessels,  have,  erroneou.sly, 
I  think,  their  actions  assigned  to  ganglionic  cells. 


252  THE  PHYSICAL  basis  of  mind. 

It  is  unnecessary  to  point  out  the  radical  misconception 
which  thus  vitiates  a  great  mass  of  anatomical  exposition 
and  pliysiological  speculation.  I  only  call  the  reader's 
attention  to  the  point  at  the  outset  of  the  brief  survey  we 
have  now  to  make  of  what  is  known  respecting  the  ele- 
mentary structure  of  the  nervous  system. 

DIFFICULTIES   OF  THE  INVESTIGATION. 

113.  So  great  and  manifold  are  the  difficulties  of  the 
search,  tliat  although  hundreds  of  patient  observers  have 
during  the  last  forty  years  been  incessantly  occupied  with 
the  elementary  structure  of  the  nervous  system,  very  little 
has  been  finally  established.  Indeed,  we  may  still  repeat 
Lotze's  sarcasm,  that  "  microscopic  theories  have  an  aver- 
age of  five  years'  duration."  This  need  not  damp  our 
ardor,  though  it  ought  to  check  a  too  precipitate  confi- 
dence. Nothing  at  the  present  moment  needs  more  rec- 
ognition by  the  student  than  that  the  statements  con- 
fidently repeated  in  text-books  and  monographs  are  very 
often  for  the  most  part  only  ingenious  guesses,  in  which 
Observation  is  to  Imagination  what  the  bread  was  to  the 
sack  in  Falstaff's  tavern  bill.  Medical  men  and  psychol- 
ogists ought  to  be  w^arned  against  founding  theories  of 
disease,  or  of  mental  processes,  on  such  very  insecure 
bases ;  and  physiological  students  will  do  well  to  remem- 
ber the  large  admixture  of  Hypothesis  which  every  de- 
scription of  the  nervous  system  now  contains.  Not  that 
the  potent  aid  of  Hypothesis  is  to  be  undervalued ;  but 
its  limits  must  be  defined.  It  may  be  used  as  a  finger- 
post, not  as  a  foundation.  It  may  suggest  a  direction  in 
which  truth  may  be  sought ;  it  cannot  take  the  place  of 
Observation.  It  may  link  together  scattered  facts ;  it 
must  not  take  the  place  of  a  fact.  We  are  glad  of  corks 
until  we  have  learned  to  swim.  We  are  glad  of  a  sugges- 
tion which  will  for  the  nonce  fill  up  the  gaps  left  by  ob- 


THE  NERVOUS  MECHANISM.  253 

servation,  and  hold  the  facts  intelligibly  together.  And 
both  as  suggestion  and  colligation,  Hypothesis  is  indis- 
pensable. Indeed,  every  discovery  is  a  verified  hypothe- 
sis ;  and  there  is  no  discovery  until  verification  has  been 
gained :  up  to  this  point  it  was  a  guess,  which  might  have 
been  erroneous  —  a  torchbearer  sent  out  to  look  for  a 
missing  child  in  one  direction,  while  the  child  was  wan- 
dering in  another ;  only  when  he  finds  the  child  can  we 
acknowledge  that  the  torchbearer  pursued  the  right  path. 
Hypothesis  satisfies  the  intellectual  need  of  an  explana- 
tion, but  we  must  be  wary  lest  we  accept  this  fulfilment 
of  a  need  as  equivalent  to  an  enlargement  of  knowledge ; 
we  must  not  accept  explanation  as  demonstration,  and 
suppose  that  because  we  can  form  a  mental  picture  of  the 
possible  stages  of  an  event,  therefore  this  picture  repre- 
sents the  actual  stages.  Let  us  be  alert,  forewarned 
against  the  tendency  to  seek  evidence  in  support  of  a 
conclusion,  instead  of  seeking  to  unfold  the  conclusion 
step  by  step  from  the  evidence.  To  seek  for  evidence  in 
support  of  a  guess  is  very  different  from  seeking  it  in  sup- 
port of  a  conehision ;  which  latter  practice  is  like  that  of 
people  asking  advice,  and  only  following  it  when  it  chimes 
in  with  their  desires. 

114.  Is  not  the  warning  needed,  when  we  find  anato- 
mists guided  by  certain  "  pliysiological  postulates,"  and 
consequently  seeing  only  what  these  postulates  demand  ? 
For  example,  there  is  tlie  postulate  of  "  isolated  conduc- 
tion," which  is  said  to  require  that  every  nerve-fibre 
should  pursue  its  course  singly  from  centre  to  periphery. 
Accordingly  the  fibres  are  described  as  unbranched. 
Whatever  may  be  the  demand  of  the  postulate,  or  the 
felt  necessity  of  the  deduction,  the  fact  is  that  nerve- 
fibres  do  branch  off  during  their  course  at  various  points ; 
nay,  it  is  doubtful  whether  any  lengthy  fibre  is  un- 
branched.    Other  postulates  demand  what  fact  plainly 


254  THE  PHYSICAL  BASIS  OF  MIND. 

denies.  It  is  said  to  be  "necessary"  that  every  cell 
sliould  have  at  least  two  fibres,  and  that  sensory  and 
motor  nerves  should  be  directly  connected  through  their 
respective  cells.  These  things  cannot  be  seen,  but  they 
are  described  with  unhesitating  precision.  Diagrams  are 
published  in  which  the  sensory  fibres  pass  into  the  cells 
of  the  posterior  horn  of  the  spinal  cord,  and  these  cells 
send  off  prolongations  to  the  cells  of  the  anterior  horn, 
and  thence  the  motor  fibres  pass  out  to  the  muscles :  an 
absolutely  impossible  arrangement,  according  to  our  pres- 
ent data!  Again,  the  postulate  that  nerve-force  originates 
in  the  cells,  and  that  nerve-functions  depend  on  cells,  re- 
quired that  the  cells  should  be  most  abundant  where  the 
function  w^as  most  energetic.  Of  course  they  were  found 
most  abundant  in  the  required  places  —  no  notice  what- 
ever being  taken  of  the  facts  which  directly  contradicted 
the  deduction. 

115.  Among  the  serious  obstacles  to  research  w^e  must 
reckon  this  tendency  to  substitute  Imaginary  Anatomy 
for  Objective  Anatomy.  I  am  conscious  of  the  tendency 
in  myself,  as  I  note  it  in  others ;  and  have  constantly  to 
struggle  against  it,  though  not  perhaps  always  aware  of 
it.  jSIany  a  time  have  I  had  to  relinquish  plausible  ex- 
planations, which  would  have  supported  my  speculations 
could  I  but  have  believed  that  they  represented  the  facts ; 
but  beins  unable  to  believe  this,  I  had  to  remember  that 
hypotheses  and  explanations  appear  and  disappear — only 
the  solid  fact  lives.  If  there  is  one  lesson  emphatically 
taught  by  Philosophy,  it  is  the  unwisdom  of  founding 
our  conclusions  on  our  desires  rather  than  on  the  objec- 
tive facts. 

116.  In  the  following  pages  a  constantly  critical  atti- 
tude is  preserved :  this  is  simply  to  keep  active  the  sense 
of  how  much  is  still  needed  to  be  done  before  a  satisfac- 
tory theory  of  the  nervous  system  can  be  worked  out. 


THE  NERVOUS  MECHANISM,  255 

The  objective  difficulties  are  greater  than  in  any  other 
department  of  Anatomy.  The  problem  is  to  form  a  pre- 
cise picture  of  what  the  organites  are,  and  of  how  they 
are  arranged  in  the  living  tissue ;  yet  our  present  means 
of  investigation  involve  as  a  preliminary  that  we  should 
alter  that  arrangement,  removing  some  elements  of  the 
tissue,  and  cluinfjing  the  state  of  others,  without  knowing 
what  were  their  precise  state  and  arrangement  before  the 
change.  Place  a  piece  of  nerve-tissue  under  the  micro- 
scope, without  having  subjected  it  to  various  mechanical 
and  chemical  operations,  and  you  can  see  next  to  nothing 
of  its  structure.  You  must  tear  the  parts  asunder,  and 
remove  the  fat  and  nerve-sap  (plasraode)  before  you  can 
see  anything;  you  must  coagulate  the  albumen,  and  other- 
wise chemically  alter  the  substances  before  a  thin  section 
can  be  made  ;  you  must  get  rid  of  the  tissues  in  which  it 
is  embedded,  without  knowing  what  are  the  connections 
tlnis  destroyed.  Living  neurine  has  no  greater  consist- 
ence than  cream,  often  no  greater  than  oil.  How,  then, 
can  thin  sections  be  made  until  this  viscid  substance  has 
been  hardened  by  alcohol  or  acids  ?  But  substances 
tluis  acted  on  lose  their  constituent  water,  which  can  no 
more  be  removed  without  alteration  of  their  structure, 
than  it  can  be  removed  from  certain  salts  witliout  de- 
struction of  their  special  properties.  Losing  their  water 
alone,  they  become  deformed.  They  lose  much  more. 
Sometimes  the  loss  can  l)e  estimated,  as  in  the  case  of 
the  hyaline  substance  investing  the  nucleus  during  the 
process  of  segmentation  in  emljryonic  cells,  which  may 
be  seen  to  disappear  when  a  weak  solution  of  acid  is  ap- 
plied.* At  other  times  we  are  unable  to  say  wliat  has 
disappeared.  Under  different  modes  of  preparation  very 
different  appearances  are  observed,  and  anatomists  are 
accordingly   at   variance.     Yet    unless    some    hardening 

*  Robin,  Anat.  el  Physiol.  Cellulaircs,  p.  332. 


25G  TIIK   PHYSICAL   BASIS   OF  MIND. 

method  be  adopted  little  can  be  seen !  Stilling,  who  has 
given  liib  lile  to  the  study,  declares  that  no  results  are 
reliable  which  are  obtained  from  the  unprepared  tissue, 
because  the  mechanical  isolation  of  the  elements  destroys 
the  textural  arrangement*  There  is  one  method  of 
hardening,  and  only  one,  which  we  can  be  certain  does 
not  chemically  alter  the  structure,  and  that  is  tlie  freezing 
method.  The  experiments  of  Dr.  Weir  Mitchell  and  Dr. 
Eichardson  prove  this,  because  they  prove  that  the  brain 
of  the  living  animal  may  be  frozen  and  frozen  again  and 
again,  yet  recover  its  vital  activity  when  tliawed.  Pro- 
fessor Eutherford  has  invented  an  admirable  instrument 
for  making  sections  of  the  frozen  tissue,  of  any  delicacy 
that  may  be  required;  but  with  the  thinnest  section  there 
will  still  be  certain  difficulties  of  observation,  unless  the 
tissue  has  undergone  a  staining  process.  Whatever  is 
seen,  however,  in  the  frozen  tissue  is  to  be  accepted  as 
normal. 

117.  Two  points  must  be  determined  before  reliance 
can  be  placed  on  observations  of  tissues  chemically  acted 
on :  First,  we  must  prove  that  the  forms  now  visible  ex- 
isted before  the  preparation  —  the  chemical  action  merely 
unveiling  them ;  secondly,  we  must  estimate  the  part 
played  by  the  elements  which  have  been  removed  in 
order  to  make  the  rest  visible.  We  know,  for  example, 
that  the  nucleus  often  exists  in  the  cell,  though  an  acid 
may  be  needed  to  make  it  visible.  We  also  know  that 
cells  which  during  life  are  quite  free  from  visible  granules 
are  distinctly  granulated  after  death,  even  without  ex- 
ternal chemical  action.  Imagine  the  explanation  of  a 
steam-engine  to  be  attempted  by  first  taking  it  to  pieces, 
and  examining  these  pieces,  with  no  account  of  the  coals 
and  steam  which  had  previously  been  removed  in  order 
to  facilitate  the  examination.     When  we  know  the  part 

*  Stilling,  Bau  der  Nervenprimitiv-Fasern,  1856,  p.  16. 


THE   NEKVOUS    MECHANISM.  257 

played  by  coals  and  steam,  we  may  disregard  these  items 
of  the  active  machine.  So  when  we  know  the  part 
played  by  water,  fat,  amorphous  substance,  and  plasmode, 
we  may  describe  nerve-tissue  without  taking  these  into 
account. 

118.  "You  have  convinced  me,"  said  Easselas  to  Imlac, 
"  that  it  is  impossible  to  be  a  poet."  My  readers  may, 
perhaps,  infer  from  this  enumeration  of  the  difficulties 
that  a  knowledge  of  the  minute  anatomy  of  the  nervous 
system  is  impossible.  Not  so ;  but  a  knowledge  of  these 
difficulties  should  impress  us  with  the  necessity  for  a 
vigilant  scepticism,  and  the  search  after  new  methods.  If 
the  difficulties  are  fairly  faced,  they  may  be  finally  over- 
come. What  we  must  resign  ourselves  to  at  present  is 
the  conviction  that  our  knowledge  is  not  sufficiently  accu- 
rate to  be  employed  as  a  basis  of  deduction  in  the  expla- 
nation of  physiological  and  psychological  processes.  * 

119.  Having  said  so  much,  let  me  add  that  there  are 
some  positive  materials,  and  these  yearly  receive  addi- 
tions. The  organites  are  described  with  a  general  agree- 
ment as  to  their  composition  and  structure  —  although 
there  is  much  that  is  hypothetical  even  here.  Neurine  is 
known  under  two  aspects  :  the  amorphous  and  the  figured. 
The  figured,  which  is  the  better  known,  comprises  cells  of 
different  kinds,  fibres  and  fibrils.  The  amorphous,  more 
generally  called  Neuroglia,  or  nerve-cement,  is  less  under- 
stood, and  is  indeed  by  many  authorities  excluded  alto- 
gether from  the  nerve-tissue  proper,  and  relegated  to  the 
class  of  connective  tissues. 

*  "There  was  a  time,"  says  Kum.ikep.,  "wlicn  I  confidently  believed 
that  an  hypothetical  ex])lanation  of  the  an'angement  of  elements  in  the 
spinal  cord  could  he  f^ioiinded  on  a  basis  of  fact ;  hut  the  deeper  my 
insight  into  the  minute  anatomy,  the  less  my  confidence  became  ;  and 
now  I  am  persuaded  that  the  time  is  not  yet  come  to  frame  such  an 
hypothesis."  —  Gewebekhrc,  5te  Auf.  18C7. 


258  THE  PHYSICVL  BASIS  OF  MIND. 


THE   NERVE-CELL. 

120.  It  is  unfortunate  that  the  term  nerve-cell  is  ap- 
plied to  organites  of  very  variable  structure.  Nerve-cell 
is  a  generic  term  of  which  the  species  are  many ;  under  it 
are  designated  organites  in  different  stages  —  as  infancy, 
childhood,  and  manhood  are  all  included  under  Man. 
Most  commonly  by  nerve-cell  is  understood  the  gan- 
glionic corpuscle,  conspicuous  in  its  size  and  its  prolon- 
gations, such  as  it  appears  in  the  great  centres,  and  in 
ganglia.  It  also  designates  smaller  different  organites, 
sometimes  called  "nuclei"  {Kcrnc),  sometimes  grains 
{Korner).  There  would  be  advantage  in  designating  the 
earlier  stages  as  neuroblasts,  reserving  the  word  cells  for 
the  more  developed  forms.  Such  a  distinction  would 
facilitate  the  discussion  of  whether  nerve-fibres  had  or 
had  not  their  origin  in  cells ;  because  while  I,  for  one,  see 
very  coercive  evidence  against  the  accepted  notion  that 
all  the  fibres  have  their  origin  in  the  processes  of  gan- 
glionic corpuscles,  I  see  no  reason  to  doubt  that  both 
fibres  and  corpuscles  have  their  origin  in  neuroblasts. 
Of  this  anon. 

The  cell  is  a  composite  organite,  the  primary  element 
being  a  microscopic  mass  of  protoplasm,  or  what  may 
more  conveniently  be  termed  neuroplasm.  It  appears  as 
finely  granulated  and  striated  or  fibrillated  substance  on 
a  hyaline  ground,  with  water,  fat,  and  diffused  pigment 
in  varying  quantities.  The  cell  contains  a  nucleus,  and 
nucleolus  —  sometimes  two.  Like  other  animal  cells,  it 
sometimes  has  a  -distinct  cell-wall,  sometimes  not.  Its 
size  and  shape  are  variable :  sometimes  distinctly  visible 
to  the  naked  eye,  generally  visible  only  under  the  micro- 
scope.*    It  is  round,  oval,  pyramidal,  club-shaped,  pear- 

*  In  the  Gasteropoda  the  cells  range  from  220  /x  to  3  /x  (/i  =  0,001 
millimetre). 


THE   NERVOUS   INIECHANISM. 


259 


shaped,  or  many-cornered.  It  has  one,  two,  three,  or 
many  outgrowths  called  "  processes,"  and  according  to  the 
processes  it  is  known  as  unipolar,  bipolar,  and  multipolar. 


Fig.  16.— Ke.rve-cell  from  anterior  horn  of  spinal  cord  (man),  magnijicd  150  diameters, 
a,  cell  process  unbranched  passing  into  or  joining  an  axis  cylinder,  the  other  pro- 
cesses are  branched  ;  6,  pigment.    The  nucleus  and  nucleolus  are  visible. 

When  there  are  no  processes  the  cell  is  called  apolar. 
Some  idea  of  these  processes  may  be  formed  if  they  are 
likened  to  the  pseudopodia  of  Amoeba  and  Foraminifera. 


?2^ 


e  is 


^      fe  - 


THE  NERVOUS  MECHANISM.  261 

Compare  Fig.  16,  a  nerve-cell,  figured  by  Gerlach,  with 
Fig.  17,  one  highly  magnified,  in  which  Max  Schultze's 
hypothesis  is  represented. 

121.  Such  is  a  general  description  of  the  nerve-cell  as 
it  is  seen  in  various  places,  and  under  various  modes  of 
preparation.  How  much  is  due  to  preparation  we  can- 
not positively  say.  Wliile  we  always  discover  fibrine 
in  the  blood  after  it  is  withdrawn  from  the  vessels,  we 
know  that  fibrine  as  such  does  not  exist  in  the  circulating 
blood.  And  if  neurine  is  a  semi-liquid  substance,  we  may 
doubt  whether  in  the  living  cell  it  is  fibrillated.  Doubts 
have  been  thrown  even  on  the  normal  existence  of  the 
granular  substance,  which  has  been  attributed  to  coagula- 
tion. Thus  we  know'  that  the  nucleus  of  the  white  blood- 
corpuscle  appears  perfectly  homogeneous  until  subjected 
to  heat,  yet  at  a  certain  temperature  (86°  F.)  it  assumes 
the  aspect  of  a  fine  network.  Haeckel  observed  the  hya- 
line substance  of  the  neurine  in  crayfish  become  troubled 
and  changed  directly  any  fluid  except  its  own  blood-serum 
came  in  contact  with  it.  Leydig  noticed  the  transparent 
ganglion  of  a  living  Daphnia  become  darker  and  darker 
as  tlie  animal  died ;  and  I  saw  something  like  this,  after 
prolonged  struggles  of  a  Daphnia  to  escape  from  a  thread 
in  which  its  leg  was  entangled.  Charles  Robin,  indeed, 
asserts  that  the  passage  from  the  hyaline  to  the  finely 
granulated  state  is  a  characteristic  of  the  dying  cell.*    On 


*  Haeckel,  Milllcr's  Archiv,  1857.  Leydig,  Voni  Bait  dcs  ihieri- 
schen  Korpcrs,  1864,  I.  84.  llonix,  Anat.  ct  Physiol.  C'eUulaircs,  p.  89. 
Should  the  observations  of  Heitzmann  be  confirmed,  tlierc  would  be 
ground  for  believing  that  neurine  is  nomially  fibrillated.  He  says  that 
the  living  ])rotoplasm  in  tlie  Anueba,  white  blood-corpuscle,  etc.,  is  an 
excessively  fine  network,  which  condenses  into  granules  at  each  contrac- 
tion. (Cited  in  the  Jahreshcrichte  iihcr  Anat.  und  Physiol.,  1873,  ]5d.  II.) 
Waltheu,  who  examined  frozen  brains,  describes  the  cells  as  ([uite  trans- 
parent at  first,  with  very  rare  granules,  but  gradually  wliih;  under  obser- 
vation the  granules  became  more  numerous.    Ccntralblatt,  1868,  p.  459. 


262  THE    PHYSICAL   BASIS   OF   MIND. 

the  other  hand,  it  should  be  noted  tliat  Max  Schultze  de- 
scribes a  fibriUated  appearance  in  cells  just  removed  from 
the  living  animal,  and  placed  in  serum. 

When,  therefore,  one  observer  describes  the  neuroplasm 
as  being  clear  as  water,  another  as  finely  granular,  and  a 
third  as  fibrillated,  we  must  conclude  that  the  observa- 
tions refer  to  cells,  1°,  under  different  states  of  vitalization, 
or,  2°,  under  different  modes  of  preparation.  On  the  first 
head  we  note  that  some  nerve- cells  are  so  perishable  that 
Trinchese  declares  he  could  find  no  cells  in  the  ganglia 
of  a  cuttlefish  which  had  been  dead  twenty-four  hours, 
although  they  were  abundant  in  one  recently  killed.*  On 
the  second  head  we  note  that  the  changes  wrought  by 
modes  of  preparation  cannot  be  left  out  of  consideration. 
Auerbach  notices  that  the  cells  and  fibres  apparent  in  the 
plexus  mycntcricus  after  an  acid  has  been  aj^plied,  cannot 
be  detected  before  that  application  —  nothing  is  visible 
but  a  pale  gelatinous  network,  with  here  and  there  knots 
of  a  paler  hue ;  and  I  remember  my  surprise  on  exam- 
ining the  fresh  spinal  cord  of  a  duck-embryo,  and  finding 
no  trace  of  cells  such  as  I  had  that  very  morning  seen  in 
the  cord  of  a  chick  of  earlier  date,  but  which  had  been 
soaked  in  weak  bichromate  of  potash.  Xow  w^e  have 
excellent  grounds  for  believing  that  in  both  cases  these 
organites  were  present,  and  that  it  was  the  reagent  which 
disclosed  their  presence  in  the  chick;  and  so  in  other 
cases  we  must  ask  wdiether  the  forms  which  appear  under 
a  given  mode  of  preparation  are  simply  iinm asked,  or  are 
in  truth  i^'oduced  by  the  reagent  ?  This  question  we  can 
rarely  answer. 

According  to  IIauthnee,  Bcitrdge  zur  Kenntniss  dcr  morpJiologischen 
Elemcntc  des  Kervcasystcrns,  1862,  p.  41,  neurine  has  three  cardinal  forms 
—  transparent,  finely  granular,  and  coarsely  granular. 

*  TiUNCHESE,  Struttura  del  sistema  nervosa  dei  Cefalopodi,  Florence, 
1868,  p.  7. 


THE   NERVOUS   MECHANISAI.  263 

If  one  of  the  very  large  cells  be  taken  from  the  gan- 
glion of  a  living  mollusc,  and  be  gently  pressed  till  it 
bursts,  the  discharged  contents  will  be  seen  to  be  of  a 
hyaline  viscid  substance,  with  fine  granules  but  no  trace 
of  fibres.  Yet  we  must  not  rashly  generalize  from  this, 
and  declare  that  in  the  vertebrate  cells  the  substance  is 
not  also  fibrillated.  As  a  good  deal  of  speculation  rests 
on  the  assumption  of  the  fibrillated  cell-contents,  I  have 
thought  it  worth  while  to  note  the  uncertainty  which 
hovers  round  it. 

122.  Among  the  uncertainties  must  be  reckoned  the 
question  as  to  the  cell-processes.  The  existence  of  apolar 
and  unipolar  cells  is  flatly  denied  by  many  writers,  who 
assert  that  the  appearances  are  due  to  the  fragility  of  the 
processes.  Fragile  the  processes  are,  and  evidence  of  their 
having  been  broken  off'  meet  us  in  every  preparation ;  but 
the  denial  of  apolar  and  unipolar  cells  seems  to  me  only 
an  example  of  the  tendency  to  substitute  hypothesis  for 
observation  (§  114).  The  "postulate"  which  some  seem 
to  regard  as  a  "  necessity  of  thought "  that  every  nerve- 
cell  shall  have  at  least  two  fibres,  one  ingoing,  the  other 
outgoing,  is  allowed  to  override  the  plain  evidence.*  It 
originated  in  the  fact  first  noticed  by  Wagner  and  Charles 
Robin  that  certain  cells  in  the  spinal  ganglia  of  fishes  are 
bipolar.  The  fact  was  rapidly  generalized,  in  spite  of  its 
not  being  verified  in  other  places ;  the  generalization  was 
accepted  because  (by  a  strange  process  of  reasoning  run- 
ning counter  to  all  physiological  knowledge)  it  was 
thought  to  furnish  an  elementary  illustration  of  the  re- 
flex process.  As  the  centre  liad  its  ingoing  and  outgoing 
nerve,  so  tlie  cell  was  held  to  be  a  centre  "  writ  small," 

*  An  eminent  friend  of  mine  was  one  flay  insisting  to  me  that  tlie  phys- 
iological postulate  made  it  impossible  for  a  nerve-cell  to  be  without  its 
ingoing  and  outgoing  fibres  ;  and  he  was  not  a  little  astounded  when  I 
replied,  "Come  into  my  workroom  and  I  will  show  you  a  thousand." 


264  TIIK    PHYSICAL    BASIS    OF    MIND. 

and  required  its  two  fibres.  No  one  paused  to  ask,  how  a 
cell  i)luced  in  the  trade  of  an  ingoing  nerve  could  fulfil 
this  otlice  of  a  reflex  centre;  no  one  supposed  that  the 
portion  of  the  sensory  fibre  which  continued  its  course, 
after  the  interruption  of  the  cell,  was  a  motor  fibre. 

What  does  Observation  teach  ?  It  teaches  that  at  first 
all  nerve-cells  are  apolar.  Even  in  the  cortex  of  the  cere- 
brum, where  (unless  we  include  the  nuclei  and  grain-like 
corjiuscles  under  cells)  all  the  cells  are  finally  multipolar, 
there  is  not  one  which  has  a  process,  up  to  the  seventh  or 
eighth  day  of  incubation  (in  the  chick) ;  from  that  day, 
and  onwards,  cells  with  one  process  appear;  later  on, 
cells  with  two,  and  later  still,  with  three.  By  this  time 
all  the  apolar  cells  have  disappeared.  They  may  there- 
fore be  regarded  as  cells  in  their  infancy.  However  that 
may  be,  we  must  accept  the  fact  that  apolar  cells  exist ; 
whether  they  can  co-operate  in  neural  functions,  is  a 
question  which  must  be  decided  after  the  mode  of  opera- 
tion of  cells  is  placed  beyond  a  doubt. 

123.  If  apolar  cells  are  embryonic  forms  of  cells  which 
afterwards  become  multipolar,  this  interpretation  will  not 
suffice  for  the  unipolar  cells.  They  are  not  only  abun- 
dant, but  are  mature  forms  in  some  organs,  and  in  some 
animals ;  though  in  some  organs  they  may  truly  be  re- 
garded as  embryonic.  Thus  in  the  human  embryo  up  to 
the  fourth  month  all  the  cells  of  the  spinal  cord  are  said 
to  be  unipolar,*  later  on  they  become  multipolar.  But  in 
birds,  rabbits,  dogs,  and  even  man,  the  cells  in  the  spinal 
ganglia  are  mainly  (if  not  wholly)  unipolar  ;t  nor  is  there 

*  EiCHHOEST  in  Virchows  Jrchiv,  1875,  LXIV.  p.  432. 

+  AuEUBACH  (Ueber  einen  Plexus  My  enter  icus,  1862)  describes  the 
ganglia  as  filled  with  apolar  cells,  among  which  only  a  few  are  unipolar. 
Stieda  {Centralncrvcnsystem  der  Vbgcl,  1868)  finds  both  apolar  and  uni- 
polar cells  in  the  spinal  ganglia  of  birds.  Axmann  {De  Gangliorum 
Systematis  Strudiira  penitiori,  1847)  says  the  spinal  cells  are  all  unipolar. 
ScHWALDE  {Archiv  fiir  mikros.  Anat.,  1868)  and  Couiia'oisieu  {ibid.. 


THE  NERVOUS  MECHANISM.  265 

any  difficulty  in  observing  the  same  fact  in  the  oesopha- 
geal ganglia  of  molluscs  (see  Fig.  22). 

Such  are  the  observations.  They  have  indeed  been 
forced  into  agreement  with  the  bipolar  postulate,  by  the 
assumption  that  the  single  process  branches  into  two,  one 
afferent,  the  other  efferent.*  But  before  making  observa- 
tion thus  pliant  to  suit  hypothesis,  it  would  be  well  to 
look  more  closely  into  the  evidence  for  the  hypothesis 
itself  For  my  own  part,  I  fail  to  see  the  justification  of 
the  postulate ;  wdiereas  the  existence  of  unipolar  cells  is 
an  observation  which  has  been  amply  verified. 

124.  Bipolar  cells  abound ;  multipolar  cells  are  still 
more  abundant ;  and  these  are  the  cells  found  in  the  gray 
substance  of  the  neural  axis.  Deiters,  in  his  epoch-mak- 
ing work,f  propounded  an  hypothetic  schema  which  has 
been  widely  accepted.  Finding  that  the  large  cells  in 
the  anterior  horn  of  the  spinal  cord  gave  off  processes  of 
different  kinds,  one  branched,  the  other  unbranched,  he 
held  that  the  latter  process  was  the  origin  of  the  axis 

1869)  say  the  same.  So  also  Ranvier,  Comptes  Rcndus,  1875.  Kolli- 
KER  {Gcicchehhre)  speaks  decidedly  in  favor  of  both  apolar  and  unipolar 
cells,  but  thinks  the  apolar  are  embryonic.  Pagliani  {Saggio  sullo  Stato 
attuale  ilclle  Cognizioni  delta  Fisiologia  intornoal  Sisteina  nervoso,  1873), 
who  represents  the  views  of  Moleschott,  admits  the  existence  of  apolar 
and  nnii)olar  cells.  The  authors  just  cited  are  those  I  happen  to  have 
liefore  me  during  the  rewriting  of  this  chapter,  and  the  list  might  easily 
be  extended  if  needful.  Auerbach,  Bidder,  and  Schwkigger-Seidel 
descrilje  unipolar  cells  which  in  some  places  present  the  aspect  of  bipolar 
cells  simply  because  two  cells  lie  together,  their  single  poles  having  op- 
posite directions.  I  will  add  that  the  bipolar  cells  do  not  really  render 
the  physiological  inter2)retation  a  whit  more  easy  than  the  unipolar,  for 
they  are  simply  cells  which  form  enlargements  in  the  cour.se  of  the  nerve- 
fibres. 

*  When  Dr.  Beai.e  .says  "that  it  is  probable  no  nerve-cell  exists  which 
has  only  one  single  fibre  connected  with  it"  (Bioplasm,  p.  186),  he  has 
no  doubt  this  in  his  mind  ;  since  he  would  not,  I  presume,  deny  that 
there  are  cells  each  with  a  single  process. 

t  Deiteus,  UntcrsucJmngen  ilbcr  Gchirn  und  Rilckcnmark,  1866. 


K. 


THE  NERVOUS  MECHANISM.  267 

cylinder  of  a  nerve-fibre,  whereas  the  branched  process 
was  protoplasm  which  divided  and  subdivided,  and  formed 
the  connection  between  one  cell  and  another.  Gerlach  has 
modified  this  by  supposing  that  the  minute  fibrils  of  the 
branching  process  reunite  and  form  an  axis  cylinder  (Fig. 
18).  There  is  no  doubt  that  some  processes  terminate  in  a 
fine  network ;  and  there  is  a  probability  (not  more)  that 
the  unbranched  process  is  always  continuous  with  the 
axis  cylinder  of  a  motor  nerve,  as  we  know  it  sometimes 
is  with  that  of  a  dark-bordered  fibre  in  the  white  sub- 
stances. This,  though  probable,  is,  however,  very  far 
from  having  been  demonstrated.  Once  or  twice  Kolliker, 
Max  Schultze,  and  Gerlach  have  followed  this  unbranched 
process  as  far  as  the  root  of  a  motor  nerve ;  and  they  infer 
that  although  it  could  not  be  traced  further,  yet  it  did 
really  join  an  axis  cylinder  tliere.  In  support  of  this  in- 
ference came  the  observations  of  Koschennikoff,*  that  in 
the  cerebrum  and  cerebellum,  processes  were  twice  seen 
continuous  with  dark-bordered  nerve-fibres.  But  the  ex- 
treme rarity  of  such  observations  amid  thousands  of  cells 
is  itself  a  ground  for  hesitation  in  accepting  a  generalized 
interpretation,  the  more  so  since  we  have  Henle's  obser- 
vation of  the  similar  entrance  of  a  branched  process  into 
the  root.f  Xow  it  must  be  remembered  that  the  branched 
process  is  by  no  anatomist  at  present  regarded  as  the 
origin  of  the  axis  cylinder;  so  that  if  it  can  enter  the 
root  without  being  the  origin  of  a  nerve-fibre,  we  are  not 
entitled  to  assume  that  the  entrance  of  the  unbranclied 
process  has  any  other  significance  (on  this  head  compare 
§  145),  especially  when  we  reflect  that  no  trustworthy 
observer  now  professes  to  have  followed  a  nerve-fibre  of 
the  posterior  root  i-iglit  into  a  multipolar  cell.     Figures, 

*  Archiv  fiir  mikros.  Armt.,  1869,  p.   217.      Compare  also  BuTZKE, 
Archivfiir  Psychiatric,  1872,  p.  584. 
t  Henle,  Nervenlehrc,  1871,  p.  58,  Fig.  21. 


268 


THE  PHYSICAL   BASIS   OF   MIND. 


indeed,  have  been  published  which  show  this,  and  much 
else ;  but  such  iigures  are  diagrams,  not  coj)ies  of  what  is 
seen.  They  belong  to  Imaginary  Anatomy.*  The  re- 
lation of  the  cell-process  to  the  nerve-fibre  will  be  dis- 
cussed anon. 

125.   A  word  in  passing  on  the  contradictory  assertions 
respecting  the  anastomosis  of  nerve-cells.      That  the  gray 


Fig.  19.  —  Anastomosing  nerve-cells  (after  Gratiolet).  a,  body  of  the  cell ;  c,  process 
of  uniting  two  cells  ;  d,  branching  process. 

substance  forms  a  contimiv/in  of  some  kind  is  certain  from 
the  continuity  of  propagation  of  a  stimulus.  But  it  is  by 
no  means  certain  that  one  cell  is  directly  united  to  its 
neighbor  by  a  cell-process.  Eminent  authorities  assert 
that  such  direct  union  never  takes  jjlace  ;  others,  that  it 
is  a  rare  and  insignificant  fact ;  others,  that  it  is  constant, 
and  "  demanded  by  physiological  postulates."     I  will  not, 

*  "When  men  of  such  experience  and  skill  as  Kolliker,  Bidder, 
GoLL,  and  Lock  hart  Clarke  declare  that  they  have  never  seen  a  cell- 
process  pa.ss  directly  into  a  dark-bordered  fibre  in  the  anterior  root,  what 
are  we  to  say  to  such  figures  and  descriptions  as  those  given  in  the  works 
of  Schroder  van  der  Kolk,  Gratiolet,  and  Llvs?  Even  did  such 
arrangements  exist,  no  transverse  nor  longitudinal  section  could  display 
them,  owing  to  the  different  planes  at  which  the  fibres  enter,  and  the 
length  and  irregularity  of  their  course. 


THE  NERVOUS  MECHANISM.  269 

in  the  presence  of  distinct  affirmations,  venture  to  deny 
that  such  appearances  as  are  presented  in  Fig.  19  may 
occasionally  be  observed ;  the  more  so  as  I  have  myself 
seen  perhaps  half  a  dozen  somewhat  similar  cases  ;  but  it 
is  the  opinion  of  Deiters  and  Kolliker  that  all  such  ap- 
pearances are  illusory.*  Granting  that  such  connections 
occur,  we  cannot  grant  this  to  be  the  normal  mode ;  espe- 
cially now  the  more  probable  supposition  is  that  the  con- 
nection is  normally  established  by  means  of  the  delicate 
ramifications  of  the  branching  processes. 

Imaginary  Anatomy  has  not  been  content  with  the  cells 
of  the  anterior  horn  being  thus  united  together,  to  admit 
of  united  action,  but  has  gone  further,  and  supposed  that 
the  cells  of  the  posterior  horn,  besides  being  thus  united, 
send  off  processes  which  unite  them  with  the  cells  of  the 
anterior  horn  —  and  thus  a  pathway  is  formed  for  the 
transmission  of  a  sensory  impression,  and  its  conversion 
into  a  motor  impulse.  What  will  the  reader  say  when 
informed  that  not  only  has  no  eye  ever  beheld  such  a 
pathway,  but  that  the  first  step  —  the  direct  union  of  the 
sensory  nerve-fil)re  with  a  cell  in  the  posterior  horn —  is 
confessedly  not  visible  ? 

126.  The  foregoing  criticisms  will  perhaps  disturb  the 
reader  who  has  been  accustomed  to  theorize  on  the  data 
given  in  text-books ;  but  he  may  henceforward  be  more 
cautious  in  accepting  such  data  as  premises  for  deduction, 
and  will  look  with  su.spicion  on  the  many  tlieories  wliich 
have  arisen  on  so  unstable  a  basis.  "When  we  rellect  how 
completely  the  modern  views  of  the  nervous  system,  and 
the  physiological,  pathological,  and  psychological  expla- 
nations based  on  tlicse  views,  are  dominated  by  tlie  cur- 

*  Long  after  tlie  text  was  written,  Willkik  publishud  in  Virchow's 
Archiv,  IST.'i,  LXIV.  p.  ]63,  observation.s  of  anastomoses  which  even 
KoLLiKEii  admitted  to  be  undeniable.  Yet  out  of  sixty-four  i)re])arations, 
amid  hundreds  of  cells,  he  could  only  reckon  seven  cases  of  conjunction. 


270  THE   niYSICAL   BASIS   OF   MIND, 

rent  notions  of  the  nerve-cell,  it  is  of  the  last  importance 
that  we  should  fairly  face  the  fact  that  at  present  our 
knowledge  even  of  the  structure  of  the  nerve-cell  is  ex- 
tremely imperfect ;  and  our  knowledge  of  the  part  it  plays 
—  its  anatomical  relations  and  its  functional  relations  — 
is  little  more  than  guesswork  ! 

THE   NEKVES. 

127.  We  now  pass  to  the  second  order  of  organites ; 
and  here  our  exposition  will  be  less  troubled  by  hesita- 
tions, for  although  there  is  still  much  to  be  learned  about 
the  structure  and  connections  of  the  nerve-fibres,  there  is 
also  a  solid  foundation  of  accurate  knowledge. 

A  nerve  is  a  bundle  of  fibres  within  a  membranous 
envelope  supplied  with  blood-vessels.  Each  fibre  has 
also  its  separate  sheath,  having  annular  constrictions  at 
various  intervals.  It  is  more  correctly  named  by  many 
French  anatomists  a  nerve-tiihe  rather  than  a  nerve-/6?'c; 
but  if  we  continue  to  use  the  term  Jibre,  we  must  reserve 
it  for  those  organites  which  have  a  membranous  sheath, 
and  thereby  distinguish  it  from  the  more  delicate  Jihnl 
which  has  none. 

The  nerve  tube  or  fibre  is  thus  constituted :  within  the 
sheath  lies  a  central  band  of  neuroplasm  identical  with 
the  neuroplasm  of  nerve-cells,  and  known  as  the  axis  cyl- 
inder ;  surrounding  this  band  is  an  envelope  of  whitish 
substance,  variously  styled  myeline,  medullary  slicath,  and 
white  substance  of  Schwann :  it  is  closely  similar  to  the 
chief  constituent  of  the  yolk  of  egg,  and  to  its  presence 
is  due  the  whitish  color  of  the  fibres,  which  in  its  absence 
are  grayish.  The  axis  cylinder  must  be  understood  as 
the  primary  and  essential  element,  because  not  only  are 
there  nerve-fibrils  destitute  both  of  sheath  and  myeline 
yet  fulfilling  the  ofiice  of  Neurility,  but  at  their  termi- 


THE  NERVOUS  MECHANISM. 


271 


X:: .  1.  M 


nations,  both  in  centres  and  in  mus- 
cles, the  nerve  -  fibres  always  lose 
sheatli  and  myeline,  to  preserve 
only  the  neuroplasmic  threads  of 
which  the  axis  cylinder  is  said  to 
be  composed.  In  the  lowest  fishes, 
in  the  invertebrates,  and  in  the  so- 
called  sympatlietic  fibres  of  verte- 
brates, there  is  either  no  myeline, 
or  it  is  not  separated  from  the  neu- 
roplasm. 

128.  Nerve-fibres  are  of  two  kinds 
—  1°.  The  darJc-hordered  or  medid- 
lary  fibres,  which  have  both  sheath 
and  myeline,  as  in  the  peripheral 
system ;  or  only  myeline,  ■without 
the  sheath,  as  in  the  central  sys- 
tem. 2°.  The  non-mcdidlary  fibres, 
which  have  the  sheath,  without  ap- 
preciable myeline  —  such  are  the 
fibres  of  the  olfactory,  and  the  pale 
fibres  of  the  sympathetic. 

Nerve-fibrils  are  neuroplasmic 
threads  of  extreme  delicacy,  visible 
only  under  high  magnil'ying  powers 
(700  -  800),  which  abound  in  the 
centres,  wliere  they  Ibrm  networks. 
The  fibrils  also  form  the  termina- 
tions of  the  fibres.  Many  fibrils 
are  supposed  to  be  condensed  in 
one  axis  cylinder.  This  is  repre- 
sented by  Max  Schultze  in  Figs. 
17  and  20. 

129.  As  may  readily  be  imag- 


Fig.    20.  —  o,   axis    cylinder 
formed  by  the  (ibrils  of  the  cell 
contents,   and  at  a'  .issuming 
the  medullary  sheath  ;?;,  naked    incd,  thc    SeUli-litplid    Uature    of  the 
axis  cylinder  from  8i>inal  cord. 


272  THE   PHYSICAL   BASIS    OF  MIND. 

neuroplasm  throws  almost  insuperable  difficulties  in  the 
way  of  accurately  determining  whetlier  the  axis  cylin- 
der in  the  living  nerve  is  fibrillated  or  not;  whether, 
indeed,  any  of  the  aspects  it  presents  in  our  prepara- 
tions are  normal.  Authorities  are  not  even  agreed  as  to 
M'hether  it  is  a  pre-existent  solid  band  of  homogeneous 
substance,  or  a  bundle  of  primitive  fibrils,  or  a  pro- 
duct of  coagulation.*  Eudanowsky's  observations  on 
frozen  nerves  convinced  him  that  the  cylinder  is  a  tubule 
with  liquid  contents.!  My  own  investigations  of  the 
nerves  of  insects  and  molluscs  incline  me  to  the  view  of 
Dr.  Schmidt  of  New  Orleans,  namely,  that  the  cylinder 
axis  consists  of  minute  granules  arranged  in  rows  and 
united  by  a  homogeneous  interfibrillar  substance,  thus 
forming  a  bundle  of  granular  fibrils  enclosed  in  a  delicate 
sheath  $  —  in  other  words,  a  streak  of  neuroplasm  whicli 
has  a  fibrillar  disposition  of  its  granules.  We  ought  to 
expect  great  varieties  in  such  streaks  of  neuroplasm ;  and 
it  is  quite  conceivable  that  in  the  Rays  and  the  Torpedo 
there  are  axis  cylinders  which  are  single  fibrils,  and  others 
which  are  bundles,  with  finely  granulated  interfibrillar 
substance.§ 

The  fibres  often  present  a  varicose  aspect,  as  represented 
in  Fig.  21.  It  is,  however,  so  rarely  observed  in  the  fresh 
tissue,  that  many  writers  regard  it  (as  well  as  the  double 
contour)  as  the  product  of  preparation.  ||  It  is,  indeed, 
always  visible  after  the  application  of  water. 

*  See  the  history  given  in  Stilling's  learned  work,  Ueber  den  Bau  der 
Kervenprimitiv-Fascr,  p.  34  ;  and  compare  Max  Schtjltze,  De  Eetince 
Slrudura,  p.  8,  and  Bau  der  NasensMeimhaut,  p.  &Q  ;  Waldeyer,  in 
the  Zeitschrift  fiir  rat.  Med.,  1863;  Li.ster  and  Turner,  Observations 
on  the  Structure  of  Nerve-Fibres,  in  Quarterly  Micros.  Journal,  1859  ; 
Ranvier,  in  the  Archives  de  Physiologic,  1872. 

t  Virchovfs  Archiv,  Bd.  LXXII.  p.  193. 

X  Monthly  Journal  of  Micros.  Science,  1874,  XI.  p.  214. 

§  Babuchin,  Centralblatt,  1868,  p.  756. 

II  Even  so  eminent  an  authority  as  W.  Krause  holds  this  both  vitli 


THE  NERVOUS  MECHANISM.  273 

"We  need  say  no  more  at  present  respecting  the  struc- 
ture of  nerve-fibres,  except  to  point  out  that  we  have  here 
an  organite  not  less  complex  than  the  cell. 


Fig.  21.  —  Nerve-fibres  from  the  ivhite  substance  of  the  cerebrum,    a,  a,  a,  tlie  medul- 
lar contents  pressed  out  of  the  tube  as  irregular  drojis. 


THE    NEUROGLIA. 

130.  Besides  cells  and  fibres,  there  is  the  amorphous 
substance,  which  constitutes  a  great  part  of  the  central 
tissue,  and  also  enters  largely  into  the  peripheral  tissue. 
It  consists  of  finely  granular  substance,  and  a  network  of 
excessively  delicate  fibrils,  with  nuclei  interspersed.  Its 
character  is  at  present  sv.h  judice.  Some  writers  hold  it 
to  be  nervous,  the  majority  hold  it  to  be  simply  one  of 
the  many  forms  of  connective  tissue :  hence  its  name 
neuroglia,  or  nerve-cement. 

regard  to  the  varicose  a.spcct  and  the  double  contour  :  Handhuch  dcr 
mcnschlichcn  Anatomic,  1876,  I.  367.  Hut.sciili,  however,  describes  the 
ner\'es  in  a  living  Nematode  as  varico.se  :  Archiv  fur  Anat.,  1873,  p.  78  ; 
iiml  I  have  .somewhere  met  with  an  observation  of  the  double  contour 
being  vi.sible  in  the  living  animal. 

12*  u 


274  THE  niYsiCAL  basis  of  mind. 

In  the  convolutions  of  the  frozen  brain  Walther  finds 
the  cells  and  fibres  imbedded  in  a  structureless  semi-fluid 
substance  ^vholly  free  from  granules ;  the  granules  only 
appear  there  ^vhen  cells  have  been  crushed.  It  is  to  this 
substance  he  attributes  the  fluctuation  of  the  living  brain 
under  the  touch,  like  that  of  a  mature  abscess ;  the  solid- 
ity which  is  felt  after  death  is  due  to  the  coagulation  of 
this  substance.  Unhappily  we  have  no  means  of  deter- 
mining whether  the  network  visible  under  other  modes 
of  investigation  is  present,  although  invisible,  in  this  sub- 
stance. The  neuroglia,  as  it  appears  in  hardened  tissues, 
must  therefore  be  described  with  this  doubt  in  our  minds. 

If  we  examine  a  bit  of  central  gray  substance  where 
the  cells  and  fibres  are  sparse,  we  see,  under  a  low  power, 
a  network  of  fibrils  in  the  meshes  of  which  lie  nerve-cells. 
Under  very  high  powers  we  see  outside  these  cells  an- 
other network  of  excessively  fine  fibrils  embedded  in  a 
granular  ground  substance,  having  somewhat  the  aspect 
of  hoar-frost,  according  to  Boll.  It  is  supposed  that  the 
first  network  is  formed  by  the  ultimate  ramifications  of 
the  nerve-cell  processes,  and  that  the  second  is  formed  by 
ramifications  of  the  processes  of  connective  cells.  In  this 
granular,  gelatinous,  fibrillar  substance  nuclei  ajDpear,  to- 
gether with  small  multipolar  cells  not  distinguishable 
from  nerve-cells  except  in  being  so  much  smaller.  These 
nuclei  are  more  abundant  in  the  tissue  of  young  animals, 
and  more  abundant  in  the  cerebellum  than  in  the  cere- 
brum. The  granular  aspect  predominates  the  fresher  the 
specimen,  though  there  is  always  a  network  of  fibrils ;  so 
that  some  regard  the  granules  as  the  result  of  a  resolution 
of  the  fibrils,  others  regard  the  fibrils  as  the  linear  crys- 
tallization (so  to  speak)  of  the  granules.* 

*  BuTZKE,  Archiv  fur  Psychiatric,  1872,  p.  594,  states  that  the 
granular  substance  has  the  chemical  composition  of  myeline.  If  this 
be  so,  we  may  suppose  the  "fibrils  of  crystallization  "  to  represent  the 


THE  NERVOUS  MECHANISM.  275 

131.  Such  is  the  aspect  of  the  neuroglia.  I  dare  not 
venture  to  formulate  an  opinion  on  the  histological  ques- 
tion whether  this  amorphous  substance  is  neural,  or  partly 
neural  and  partly  connective  (a  substance  "which  is  poten- 
tially both,  according  to  Deiters  and  Henle),  or  wholly 
connective.  The  question  is  not  at  present  to  be  an- 
swered decisively,  because  what  is  known  as  connective 
tissue  has  also  the  three  forms  of  multipolar  cells,  fibrils, 
and  amorphous  substance ;  nor  is  there  any  decisive  mark 
by  which  these  elements  in  the  one  can  be  distinguished 
from  elements  in  the  other.  The  physical  and  chemical 
composition  of  Xeurogiia  and  Neuroplasm  are  as  closely 
allied  as  their  morphological  structure.  And  although  in 
the  later  stages  of  development  the  two  tissues  are  mark- 
edly distinguishable,  in  the  early  stages  every  effort  has 
failed  to  furnish  a  decisive  indication.*  Connective  tissue 
is  dissolved  by  solutions  which  leave  nerve-tissue  intact. 
Can  we  employ  this  as  a  decisive  test  ?  No,  for  if  we 
soak  a  section  of  the  spinal  cord  in  one  of  these  solutions, 
the  ^:)w  mater  and  the  membranous  septa  which  ramify 
from  it  between  the  cells  and  fibres  disappear,  leaving  all 
the  rest  unaltered.  This  proves  that  Neuroglia  is  at  any 
rate  chemically  different  from  ordinary  connective  tissue, 
and  more  allied  to  the  nervous.  As  to  the  staining 
process,  so  much  relied  on,  nothing  requires  greater  cau- 
tion in  its  employment.  Stieda  found  that  the  same 
parts  were  sometimes  stained  and  sometimes  not ;  and 
Mauthner  observed  that  in  some  cells  both  contents  and 
nucleolus  were  stained,  while  the  nucleus  remained  clear, 

coagulation  of  the  substance  which  is  in  solution  amid  the  inyeline  gran- 
ules, and  corresponds  with  the  axis  cylinder  of  a  fibre.  I  may  remark 
that  in  almost  every  good  prejjaration  nerve-cells  will  be  found  in  which, 
while  one  process  is  distinctly  granular,  another  is  striated  or  even 
fibrillated. 

*  Boll,  Die  Ilisliologic  und  Ilisliogcncsc  dcr  ncrvosen  Ccntralorganc, 
in  the  Archiv  fiir  Psychiatric,  1873,  p.  47. 


276  THE   niYSICAL   BASIS   OF   MIND. 

in  other  cells  the  contents  remained  clear ;  and  some  of 
the  axis  cylinders  were  stained,  the  others  not*  Lister 
found  that  the  connective  tissue  between  the  fibres  of  the 
sciatic  nerve,  as  well  as  the  'pia  mater,  were  stained  like 
the  axis  cylinders ;  f  and  in  one  of  my  notes  there  is  the 
record  of  both  (supposed)  connective  cells  and  nerve-cells 
being  stained  alike,  while  the  nerve-fibres  and  the  (sup- 
posed) connective  fibres  were  unstained.  Whence  I  con- 
clude that  the  supposition  as  to  the  nature  of  the  one 
group  being  different  from  that  of  the  other  was  unten- 
able, if  the  staining  test  is  to  be  held  decisive. 

132.  The  histological  question  is  raised  into  undue  im- 
portance because  it  is  supposed  to  carry  with  it  physio- 
logical consequences  which  would  deprive  the  neuroglia 
of  active  co-operation  in  neural  processes,  reducing  it 
to  the  insignificant  position  of  a  mechanical  support.  I 
cannot  but  regard  this  as  due  to  the  mistaken  tendency 
of  analytical  interpretation,  which  somewhat  arbitrarily 
fastens  on  one  element  in  a  complex  of  elements,  and 
assigns  that  one  as  the  sole  agent.  Whether  we  call  the 
neuroglia  connective  or  neural,  it  plays  an  essential  part  in 
all  neural  processes,  probably  a  more  important  part  than 
even  the  nerve-cells,  which  usurp  exclusive  attention ! 
To  overlook  it,  or  to  assign  it  a  merely  mechanical 
office,  seems  to  me  as  unphysiological  as  to  overlook 
blood-serum,  and  recognize  the  corpuscles  as  the  only 
nutrient  elements.  The  notion  of  the  neuroglia  being  a 
mere  vehicle  of  support  for  the  blood-vessels  arises  from 
not  distinguishing  between  the  alimental  and  instru- 
mental  offices.  In  the  function  of  a  limb,  bone  is  a  co- 
operant.  In  the  function  of  a  centre,  connective  tissue 
is  a  co-operant ;  so  that  even  if  we  acknowledge  neuroglia 

*  Stieda,  Sludien  iiher  das  Ccntrahicrvensystem  der  Vogel,  1868,  p. 
65.     Mauthner,  Op.  cit.,  p.  4. 
t  TuiiNEU  and  Lister,  Op.  cit.,  p.  8. 


THE  KERVOUS  MECHANISM.  277 

to  be  a  special  form  of  connective  tissue,  it  is  an  agent  in 
neural  processes ;  ichat  its  agency  is,  will  be  hereafter 
considered. 

Following  Bidder  and  Kupffer,  the  Dorpat  school  pro- 
claimed the  wliole  of  the  gray  substance  of  the  posterior 
half  of  the  spinal  cord  to  be  connective  tissue ;  and  Bles- 
sig  maintained  that  the  whole  of  the  retina,  except  the 
optic  fibres,  was  connective  tissue.*  Even  those  anato- 
mists who  regarded  this  as  exaggerated,  admitted  that 
connective  tissue  largely  enters  into  the  gray  substance, 
especially  if  the  granular  ground  substance  be  reckoned 
as  connective,  the  nerve-cells  being  very  sparse  in  the 
posterior  region.  Be  it  so.  Let  us  admit  tliat  the  gray 
matter  of  the  frog's  spinal  cord  is  mainly  composed  of 
neuroglia,  in  which  a  very  few  multijDolar  nerve-cells  are 
embedded.  What  must  our  conclusion  be  ?  Why,  that 
since  this  spinal  cord  is  proved  to  be  a  centre  of  ener- 
getic and  manifold  reflex  actions  —  even  to  the  extent  of 
forcing  many  investigators  to  attribute  sensation  and  voli- 
tion to  it — this  is  proof  that  connective  tissue  does  the 
work  of  nerve-tissue,  and  that  the  neuroglia  is  more  impor- 
tant than  nerve-cells ! 

Three  hypotheses  are  maintainable  —  1°.  The  neuroglia 
is  the  amorphous  ground-substance  of  undeveloped  tissue 
(neuroplasm)  out  of  which  the  cells  and  fibres  of  nerve- 
ti.ssue  and  connective  tissue  are  evolved.  2°.  It  is  the 
product  of  dissolved  nerve  cells  and  fibres.  3°.  It  is  the 
undeveloped  stage  of  connective  tissue.  For  physiologi- 
cal purposes  we  may  adopt  any  one  of  these  views,  pro- 
vided we  keep  firm  hold  of  the  fact  that  tlie  neuroglia  is 
an  essential  element,  and  in  the  centres  a  dominant 
element.  To  make  this  clear,  however,  we  must  inquire 
more  closely  into  the  relations  of  the  three  elements, 
nerve-cells,  fibres,  and  neuroglia. 

*  Blessig,  De  RetincB  Struclura,  1857. 


278  THE   niYSICAL   BASIS   OF  MIND. 


THE   RELATIONS   OF   THE   ORGANITES. 

133.  In  eimnierating  among  the  obstacles  to  research 
the  tendency  to  substitute  hyiDothetic  deductions  in  place 
of  objective  facts,  I  had  specially  in  my  mind  the  wide- 
reaching  influence  of  the  reigning  theories  of  the  nerve- 
cell.  Had  we  a  solidly  established  theory  of  the  cell, 
eg^uivalent,  say,  to  our  theory  of  gas-pressure,  we  should 
still  need  caution  in  allowing  it  to  override  exact  obser- 
vation ;  but  insecure  as  our  data  are,  and  hypotlietical  as 
are  the  inferences  respecting  the  part  played  by  the  cell, 
the  reliance  placed  on  deductions  from  such  premises  is 
nothing  less  than  superstition.  Science  will  take  a  new 
start  when  the  whole  question  is  reinvestigated  on  a  pre- 
liminary setting  aside  of  all  that  has  been  precipitately 
accepted  respecting  the  office  of  the  cell.  This  exercise 
of  the  imagination,  even  should  the  reigning  theories 
subsequently  be  confirmed,  would  not  fail  to  bring  many 
neglected  facts  into  their  rightful  place. 

I  am  old  enough  to  remember  when  the  cell  held  a 
very  subordinate  position  in  Neurology,  and  now  my 
meditations  have  led  me  to  return,  if  not  to  the  old  views 
of  the  cell,  at  least  to  something  like  the  old  estimate  of 
its  relative  importance.  Its  existence  was  first  brought 
prominently  forward  by  Ehrenberg  in  1834,  who  de- 
scribed its  presence  in  the  sympathetic  ganglia;  and  by 
liemak  in  1837,  who  described  it  in  the  spinal  ganglia. 
For  some  time  afterwards  the  ganglia  and  centres  were 
said  to  contain  irregular  masses  of  vesicular  matter  which 
were  looked  on  as  investing  the  fibres ;  what  their  office 
was,  did  not  appear.  But  there  rapidly  arose  the  belief 
that  the  cells  were  minute  batteries  in  which  "nerve- 
force  "  was  developed,  the  fibres  serving  merely  as  con- 
ductors.    Once  started  on  this  track,  Hypothesis  had  free 


THE  NERVOUS  MECHANISM.  279 

way,  and  a  sort  of  fetichistic  deification  of  the  cell  in- 
vested it  with  miraculous  powers.  In  many  works  of 
repute  we  meet  with  statements  which  may  fitly  take 
their  place  beside  the  equally  grave  statements  made  by 
savages  respecting  the  hidden  virtues  of  sticks  and  stones. 
We  find  the  ner\e-cells  credited  with  "metabolic  powers," 
which  enable  them  to  "spiritualize  impressions,  and  ma- 
terialize ideas,"  to  transform  sensations  into  movements, 
and  elaborate  sensations  into  thoughts ;  not  only  have 
they  this  "remarkable  aj)titude  of  metabolic  local  action," 
tliey  can  also  "  act  at  a  distance."  *  The  savage  believes 
that  one  pebble  will  cure  diseases,  and  another  render  him 
victorious  in  war ;  and  there  are  pliysiologists  who  believe 
that  one  nerve-cell  has  sensibility,  another  motricity,  a 
third  instinct,  a  fourth  emotion,  a  fifth  reflexion :  they 
do  not  say  this  in  so  many  words,  but  they  assign  to  cells 
which  differ  only  in  size  and  sliape,  specific  qualities. 
They  describe  sensational,  emotional,  ideational,  sympa- 
thetic, reflex,  and  motor-cells ;  nay,  Schroder  van  der 
Kolk  goes  so  far  as  to  specify  hunger-cells  and  thirst- 

*  LuYs,  HccJierches  sur  Ic  Sijstbne  nerveux,  1865,  p.  267.  In  a  recent 
and  remarkable  treatise  the  student  is  informed  that  "plusune  cellule 
est  chargee  d'un  rule  purement  mecanique  plus  elle  est  voluniinouse  ; 
plus  I'acte  qu'elle  produit  tend  a  revetir  un  caractere  psychique  plus  olio 
est  petite "  ;  to  move  a  limb  the  agitation  of  the  cerebral  cells  must 
tnatcricdize  itself  more  and  more,  "  11  a  besoin  de  passer  par  des  cellules, 

de  moins  en  moins  spirituellcs  et  de  plus  en  jilus  matf'ricUes Do 

ineme   pour   les   cellules   sensitives.     L'im])ression   exterieure  va  en  se 

modifiant,  en   se  spiritualisant,  de  la  peripheric  au  centre Un 

phenomene  de  I'ordre  spirituel  ne  saiirait  devenir  sans  transition  un 
jihenomene  d'ordre  physi([ue."  And  what  is  this  marvellous  transition 
between  spiritual  and  physical  ?  It  is  the  action  of  medium-sized  cells 
which  "travaillent  la  vibration  re9ue,  la  modifient  de  fa(;on  a  lui  Oter 
de  son  spiritualismc  et  a  la  rapprocher  davantage  des  ebranlemeiits  phy- 
siques." I  will  not  name  tl)e  estimable  author,  because  he  is  simply 
restating  what  many  others  imjAicitly  or  explicitly  teach  ;  but  I  will 
oidy  ask  the  reader  to  try  and  realize  in  thought  the  process  thus 
described. 


280  THE  PHYSICAL   BASIS   OF   MIND. 

cells.*     With   \vluit   grace   can   these   writers   laugh  at 
Scholasticism  ? 

134.  The  hypothesis  of  the  nerve-cell  as  the  fountain 
of  nerve-force  is  supported  by  the  gratuitous  hypothesis  of 
cell-substance  having  greater  chemical  tension  and  molec- 
ular instability  than  nerve-fibre.  No  evidence  has  been 
furnished  for  this ;  indeed  the  only  experimental  evidence 
bearing  on  this  point,  if  it  has  any  force,  seems  directly 
adverse  to  the  hypothesis.  I  allude  to  tlie  experiments 
of  Wundt,  which  show  that  the  faint  stimulus  capable 
of  moving  a  nmscle  when  applied  directly  to  its  nerve, 
must  be  increased  if  the  excitation  has  to  pass  through 
the  cells  by  stimulation  of  the  sensory  nerve.f  Wundt 
interprets  this  as  proving  that  the  cells  retard  every  im- 
pulse, whereby  they  are  enabled  to  store  up  latent  force. 
The  cells  have  thus  the  office  of  locks  in  a  canal,  which 
cause  the  shallow  stream  to  deepen  at  particular  places. 
I  do  not  regard  this  interpretation  as  satisfactory;  but 
the  fact  at  any  rate  seems  to  prove  that  so  far  from  the 
cells  manifesting  greater  instability  than  the  fibres,  they 
manifest  less. 

135.  The  hypothesis  of  nerve-force  being  developed  in 
the  ganglia,  gradually  assumed  a  more  precise  expression 
when  the  nerve-cells  were  regarded  as  the  only  important 
elements  of  a  ganglion.  It  has  become  the  foundation- 
stone  of  Xeurology,  therefore  very  particular  care  should 
be  taken  to  make  sure  that  this  foundation  rests  on  clear 
and  indisputable  evidence.  Instead  of  that,  there  is  ab- 
solutely no  evidence  on  which  it  can  rest ;  and  tliere  is 
much  evidence  decidedly  opposed  to  it.     Neither  struc- 

*  Schroder  van  der  Kolk,  Pathologic  der  Geisteshrankheiten,  1863, 
p.  69. 

t  WuxDT,  Physiologischc  Psyclwlogie,  p.  261.  In  his  Meclianik  der 
Nerven,  2  AUh.  (published  just  as  this  sheet  is  going  to  press),  he  shows 
that  a  stimulus  is  both  retarded  and  weakened  in  its  passage  through  a 
ganglion. 


THE  NERVOUS  MECHANISM. 


281 


ture  nor  experiment  points  out  the  cells  as  the  chief 
agents  in  neural  processes.     Let  us  consider  these. 

Fig.  22  sliows  the  contents  of  a  molluscan  ganglion 
which  has  been  teased  out  with  needles. 


Fig.  22.  —  Cells,  fibres,  and  amnrphous  mihstirncf  ftam  the  gnnglion  of  a  mollusc 
(uftcr  Uucholtz). 


282 


THE   PHYSICAL   BASIS   OF   MIND. 


The  cells  are  seen  to  vary  in  size,  but  in  all  there  is  a 
rim  of  neuroplasm  surroiinding  the 
larire  nucleus,  and  from  this  neuro- 
plasm  the  fibre  is  seen  to  be  a  pro- 
longation. The  dotted  substance  in 
the  centre  is  the  neuroglia.  Except 
in  the  possession  of  a  nucleus,  there 
is  obviously  here  no  essential  differ- 
ence in  the  structure  of  cell  and  fibre. 

Now  compare  this  with  Fig.  23,  rep- 
resenting three  fibres  from  the  audi- 
tory nerve. 

Here  the  cell  substance,  as  Max 
Schultze  remarks,  "is  a  continuation 
of  the  axis  cylinder,  and  encloses  the 
nucleus.  The  medulla  commonly  ceases  g 
at  the  point  where  the  axis  enters  the 
cell,  to  reappear  at  its  exit;  but  it 
sometimes  stretches  across  the  cell  to 
enclose  it  also :  so  that  such  a  gan- 
glion cell  is  in  truth  simply  the  nu- 
cleated portion  of  the  cylinder  axis."* 
There  are  many  places  in  which  fibres 
are  thus  found  with  cells  inserted  in 
their  course  as  swellings  :  in  the  spinal 
ganglia  of  fishes  these  are  called  bi- 
polar cells ;  they  are  sometimes  met 
with  even  in  the  cerebellum ;  but 
oftener  in  peripheral  nerves,  where 
they  are  mostly  small  masses  of  gran- 
ular neuroplasm  from  which  usually  aZtorTZrtl^^^^l 
a  branching  of  the  fibre  takes  place,  cylinder ;  &,  the  ceUniar  en- 

rrii  ...  1  •    1        ,,        ,•  .  n     1    larj;ement ;  c,  the  medullary 

Ine  pomt  to  which  attention  is  called  sheath. 

*  Trinchese  also  says  that  the  fibres   "provengono  dalle  cellule  e 
non  son  altro  che  i  loro  jrrolungamenti  o  poli."  —  Op.  cit.,  p.  13.     An 


THE  NERVOUS  MECHANISM.  283 

is  that  in  some  cases,  if  not  in  all,  the  nerve-fibre  is 
structurally  continuous  with  the  cell  contents.  The 
two  organites  —  fibre  and  cell  —  differ  only  as  regards 
the  nucleus  and  pigment.  Haeckel,  who  affirms  that 
in  the  crayfish  [Astacus  Jluviatilis)  he  never  saw  a  cell 
which  did  not  continue  as  a  fibre,  thinks  there  is  al- 
ways a  marked  separation  of  the  granular  substance 
from  its  "  hyaline  protoplasm,"  and  that  only  this  latter 
forms  the  axis  cylinder.  But  although  my  observations 
agree  with  this  as  a  general  fact,  I  have  seen  even  in 
crayfish  the  granular  substance  prolonged  into  the  axis 
cylinder;  and  in  other  animals  the  granular  substance 
is  frequently  discernible. 

Indeed  it  may  be  said  that  anatomists  are  now  tolera- 
bly unanimous  as  to  the  axis  cylinder  being  identical 
with  the  protoplasmic  cell  substance.  If  this  be  so,  we 
have  only  to  recall  the  principle  of  identity  of  property 
accompanying  identity  of  structure,  to  conclude  that 
■whatever  properties  ive  assign  to  the  cells  (unless  we  restrict 
these  to  the  nucleus  and  pigment)  ive  must  assign  to  the 
axis  cylinders.  We  can  therefore  no  longer  entertain  the 
hopothesis  of  the  cells  being  the  fountains  or  reservoirs 
of  Neurility ;  the  less  so  when  we  reflect  that  cells  do 
not  form  the  hundredth  part  of  nerve-tissue:  for  even  the 
gi'ay  substance  Itears  but  a  small  proportion  to  the  white; 
and  of  the  gray  substance,  Henle  estimates  that  one  lialf 
is  fibrous,  the  rest  is  partly  cellular,  partly  amor])Iious. 
Those  who  derive  Neurility  irom  the  cells,  forget  that 
although  the  organism  begins  as  a  cell,  and  for  some 
weeks  consists  mainly  of  cells,  yet  from  this  time  onwards 
there  is  an  ever-increasing  preponderance  of  cell-deriva- 
tives —  fibres,  tubes,  and  amorphous  substance  ■ —  and  cor- 

unequivocal  exanijilc  is  socn  in  the  Torpedo,  where  the  large  cell.s  have 
each  their  prolongation  continuing  without  interruption  into  the  elec- 
trical organ.  See  the  figure  given  hy  Ueiciieniieim  in  the  Archiv  filr 
Anat.,  1873,  Het't  VI. 


284  THE  PHYSICAL  BASIS   OF  MIND. 

responding  with  this  is  the  ever-increasing  power  and 
complexity  of  tlie  organism. 

13G.  From  another  point  of  view  we  must  reject  the 
hypothesis.  Not  only  does  the  evidence  which  points 
to  the  essential  continuity  in  structure  of  nerve  cell  and 
fibre  discredit  the  notion  of  their  physiological  diversity, 
but  it  is  further  supported  by  the  fact  that  although  the 
whole  nervous  system  is  structurally  continuous,  an  im- 
mense mass  of  nerve-fibres  have  no  immediate  connection 
with  ganglionic  cells :  —  neither  springing  from  nor  ter- 
minating in  such  cells,  their  activity  cannot  be  assigned 
to  them.  To  many  readers  this  statement  will  be  start- 
ling. They  have  been  so  accustomed  to  hear  that  every 
fibre  begins  or  terminates  in  a  cell,  that  a  doubt  thrown 
on  it  will  sound  paradoxical.  But  there  is  an  equivoque 
liere  which  must  be  got  rid  of.  When  it  is  said  that 
every  fibre  has  its  "  origin "  in  a  cell,  this  may  be  true 
if  origin  mean  its  point  of  deijcirture  in  evolution,  for 
"  cells  "  are  the  early  forms  of  all  organites ;  but  although 
every  organite  is  at  first  a  cell,  and  in  this  sense  a  nerve- 
fibre  must  be  said  to  orioinate  in  a  cell,  we  must  guard 
against  the  equivoque  which  arises  from  calling  the 
highly  differentiated  organite,  usually  designated  gangli- 
onic cell,  by  the  same  name  as  its  starting-point.  On 
this  ground  I  suggest  the  term  neuroblast,  in  lieu  of 
nerve-cell,  for  the  earlier  stages  in  the  evolution  of  cell 
and  fibre.  Both  Embryology  and  Anatomy  seem  to  show 
that  cell  and  fibre  are  organites  differentiated  from  iden- 
tical neuroblasts,  with  a  somewhat  varying  history,  so 
that  in  their  final  stages  the  cell  and  fibre  have  con- 
spicuous differences  in  form  with  an  underlying  identity ; 
just  as  a  male  and  female  organism  starting  from  identi- 
cal ova,  and  having  essential  characters  in  common,  are 
yet  in  other  characters  conspicuously  unlike.  The  mul- 
tipolar cell  is  not  necessarily  the  origin  of  a  nerve-fibre, 


THE  NERVOUS  MECHANISM.  285 

although  it  is  probable  that  some  short  fibres  have  their 
origin  ill  the  prolongations  of  cells.  Although  the  latter 
point  has  not,  I  think,  been  satisfactorily  established, 
except  in  the  invertebrata,  I  see  no  reason  whatever  to 
doubt  its  probability ;  what  seems  the  least  reconcilable 
with  the  evidence  is  the  notion  that  all  fibres  arise  as 
prolongations  from  ganglionic  cells,  instead  of  arising 
independently  as  differentiations  from  neuroblasts.  The 
reader  will  observe  that  my  objection  to  the  current  view 
is  purely  anatomical ;  for  the  current  view  would  suit  my 
physiological  interpretations  equally  well,  and  would  be 
equally  irreconcilable  with  the  hypothesis  of  the  cell  as 
the  source  of  Neurility,  so  long  as  the  identity  of  struc- 
ture in  the  axis  cylinder  and  cell  contents  is  undisputed. 
137.  The  evidence  at  present  stands  thus :  There  are 
numerous  multipolar  cells  which  have  no  traceable  con- 
nection with  nerve-fibres ;  and  fibres  which  have  no 
direct  connection  with  multipolar  cells.  By  the  first  I 
do  not  mean  the  disputed  apolar  cells,  I  mean  cells  in 
the  gray  substance  of  tlie  centres  which  send  off  pro- 
cesses that  subdivide  and  terminate  as  fibrils  in  the  net- 
work of  the  Neuroglia  (Figs.  16,  18).  It  is  indeed  gen- 
erally assumed  that  tliese  have  each  one  process  —  the 
axis-cylinder  process  —  which  is  prolonged  as  a  nerve- 
fibre  ;  nor  would  it  be  prudent  to  assert  that  such  is 
never  the  case ;  though  it  would  be  difficult  to  distin- 
guish between  a  fibre  wliich  had  united  with  a  process 
and  a  fibre  which  was  a  prolongation  of  a  process,  in  both 
cases  the  neuroplasm  being  identical.  I  only  urge  that 
the  assumption  is  grounded  not  on  anatomical  evidence, 
but  on  a  supposed  necessary  postulate.  All  that  can  be 
demonstrated  is  that  some  processes  terminate  in  exces- 
sively fine  fibrils  ;  and  occasionally  in  tliousands  of  speci- 
mens processes  liave  been  traced  into  dark-bordered  fibres. 
It   is  true  that   they  often  present  appearances  which 


286  THE   PHYSICAL   BASIS   OF   MIND. 

have  led  to  the  inference  that  they  did  so  terminate  — 
appearances  so  deceptive  that  Golgi  and  Arndt  inde- 
pendently record  observations  of  unbrauched  processes 
having  the  aspect  of  axis  cylinders  being  prolonged  to 
a  considerable  distance  (600  fj,  in  one  case),  yet  these 
were  found  to  terminate  not  in  a  dark-bordered  fibre,  but 
in  a  network  of  fibrils.* 

138.  While  it  is  thus  doubtful  whether  dark -bordered 
fibres  are  always  immediately  connected  with  cells,  it 
is  demonstrable  that  multitudes  of  fibres  have  only  an 
indirect  connection  with  cells,  being  developed  as  out- 
growths from  other  fibres.  Dr.  Beale  considers  that  in 
each  such  outgrowths  have  their  origin  in  small  neuro- 
plasmic  masses  (his  "germinal  matter").  That  is  an- 
other question.  The  fact  here  to  be  insisted  on  is  that 
we  often  find  groups  of  cells  with  only  two  or  three  fibres, 
and  groups  of  fibres  where  very  few  cells  exist.  Schro- 
der van  der  Kolk  says  that  in  a  sturgeon  {Accipenser  stu- 
rio)  weighing  120  pounds  he  found  the  spinal  cord  scarcely 
thicker  than  that  of  a  frog ;  the  muscles  of  this  fish  are 
enormous,  and  its  motor  nerves  abundant;  yet  these 
nerves  entered  the  cord  by  roots  no  thicker  than  a  pig's 
bristle ;  and  in  the  very  little  gray  matter  of  the  cord 
there  was  only  a  cell  here  and  there  found  after  long 
search.  Are  we  to  suppose  that  these  rare  cells  were  the 
origins  of  all  the  motor  and  sensory  nerves  ?  A  similar 
want  of  correspondence  may  be  noticed  elsewhere.  Thus 
in  the  spinal  cord  of  the  Lamprey  my  preparations  show 

*  Golgi,  Sulla  struttura  della  sostanza  grizia  del  Cervello.  Arndt, 
Archivfilr  mikros.  Anat.  1870,  p.  176.  Rindfleiscii  also  traces  these 
processes  into  the  neuroglia  (lirf?.,  1872,  p.  453).  "Deiters,  Boddaert, 
and   other   observers   have    stated  that   one    dark-bordered    nerve-fibre 

enters  each  cell My  own  observations  lead  me  to  conclude  that  all 

the  fibres  are  composed  of  the  same  material,  but  that  one  fibre  does  not 
divide  until  it  has  passed  some  distance  from  the  cell,  while  others  give 
off  branches  much  closer  to  it."  —  Beale,  Bioplasm,  p.  189. 


THE  NERVOUS  MECHANISM.  287 

very  few  cells  in  any  of  the  sections,  and  numerous  sec- 
tions show  none  at  all.  Stieda  counted  only  eight  to 
ten  cells  in  each  horn  of  some  osseous  fishes,  except  at 
the  places  where  the  spinal  roots  emerged.  In  the  eel 
and  cod  he  found  parts  of  the  cord  quite  free  from  cells, 
and  in  other  parts  found  two,  three,  never  more  than  ten. 
In  birds  he  counted  from  twenty-five  to  thirty.  Par- 
ticular attention  is  called  to  this  fact  of  the  eel's  cord 
being  thus  deficient,  because  every  one  knows  the  ener- 
getic reflex  action  of  that  cord,  each  separate  segment  of 
which  responds  to  peripheral  stimulation. 

It  may  indeed  be  urged  that  these  few  cells  were  the 
origin  of  all  the  fibres,  the  latter  having  multiplied  by 
the  well-known  process  of  subdivision ;  and  in  support 
of  this  view  the  fact  may  be  cited  of  the  colossal  fibres 
of  the  electric  fishes,  each  of  which  divides  into  five-and- 
twenty  fibres,  and  in  the  electric  eel  each  fibre  is  said  by 
Max  Schultze  to  divide  into  a  million  of  fibrils.  But  I 
interpret  this  fact  otherwise.  It  seems  to  me  to  prove 
nothing  more  than  that  the  neuroplasm  has  differentiated 
into  few  cells  and  many  fibres.  And  my  opinion  is 
grounded  on  the  evidence  of  Development,  presently  to 
be  adduced.  If  we  find  (and  this  we  do  find)  fibres 
making  their  appearance  anywhere  before  multipolar  cells 
appear,  tlie  question  is  settled. 

139.  Dr.  Beale  regards  the  large  caudate  cells  of  the 
centres  as  different  organites  from  the  oval  and  pyriform 
cells,  and  thinks  they  are  probably  stations  through  wliich 
fibres  having  different  origins  merely  pass,  and  change 
their  directions ;  and  Max  Schultze  says  that  no  single 
fibril  has  been  found  to  have  a  central  origin  ;  every 
fibril  arises  at  the  periphery,  and  passes  through  a  cell, 
which  is  thus  crossed  by  different  fibrils.*  (Comp.  Fig.  17.) 

*  Beale,  Bioplasm,  p.  177.     Max  Sciu.'mze,  in  Strieker's  Ilandbueh, 
p.  134.     Com\>.^T:ihi.iS(i,  Nervenprimitiv-Faser,\}.\ZZ.     Aksbt,  Archiv 


288  THE  niYsiCAL  basis  of  mind. 

The  teaching  of  Development  is  on  this  point  of  su- 
preme importance.  Unhappily  there  has  not  yet  been  a 
sullicient  collection  of  systematic  observations  to  enable 
us  to  speak  very  confidently  as  to  the  successive  stages, 
but  some  negative  evidence  tliere  is.  The  changes  take 
place  with  great  rapidity,  and  the  earliest  stages  have 
hardly  been  observed  at  all.  Although  for  several  succes- 
sive years  I  watched  the  development  of  tadpoles,  the 
difficulties  were  so  great,  and  the  ajDpearances  so  perplex- 
ing, that  the  only  benefit  I  derived  was  that  of  being  able 
the  better  to  understand  the  more  successful  investiga- 
tions of  others.  Four  or  five  days  after  fecundation  is  the 
earliest  period  of  which  I  have  any  recorded  observation  ; 
at  this  period  the  cerebral  substance  appeared  as  a  finely 
granular  matter,  having  numerous  lines  of  segmentation 
marking  it  off  into  somewhat  spherical  and  oval  masses, 
interspersed  with  large  granules  and  fat  globules.  Here 
and  there  hyaline  substance  appeared  between  the  seg- 
ments. Similar  observations  have  since  been  recorded  by 
Charles  Robin  in  the  earliest  stages  of  the  Triton.*  He 
says  that  when  the  external  gills  presented  their  first 
indications,  nuclei  appeared,  each  surrounded  by  a  rim  of 
hyaline  substance,  from  which  a  pale  filament  was  pro- 
longed at  one  end,  sometimes  one  at  both  ends,  and  this 
filament  subdivided  as  it  grew  in  length  until  it  had  all 
the  appearance  of  an  axis  cylinder.  This,  however,  he 
says,  is  a  striation,  not  a  fibrillation  ;  he  refuses  to  admit 
that  the  axis  cylinder  is  a  bundle  of  fibrils.  He  further 
notices  the  simultaneous  appearance  of  amorphous  sub- 

fiir  mikros.  Anat.,  1868,  p.  512  ;  and  1869,  p.  237.  "Weighty  as  these 
authorities  are,  their  view  is  questionable  —  firstly,  because  tlie  forms  of 
these  cells  are  too  constant  and  definite  in  particular  places  to  result 
from  the  union  of  fibrils  coming  from  various  origins  ;  but  secondly,  and 
mainly,  because  the  teaching  of  Development  is  opposed  to  it. 
*  KoBiN,  A'/iat.  et  Physiol.  Ccllulaires,  p.  335. 


THE  NERVOUS  MECHANISM.  289 

stance ;  and  as  this  is  several  days  before  there  is  any 
trace  of  a  ^jm  mater,  or  proper  connective  tissue,  he  urges 
this  among  the  many  considerations  which  should  prevent 
the  identification  of  neuroglia  with  connective  tissue. 

In  a  very  young  embryo  of  a  mole  (I  could  not  deter- 
mine its  age)  the  cortex  of  the  hemispheres  showed 
granular  amorphous  substance,  in  whicli  were  embedded 
spherical  masses  of  somewhat  paler  color,  which  had  no 
nuclei,  and  were  therefore  not  cells.  Besides  these,  there 
were  nucleated  masses  (apolar  cells,  therefore)  and  more 
developed  cells,  unipolar,  bipolar,  and  tri polar.  Not  a 
trace  of  a  nerve-tibre  was  visible.  In  agreement  with  this 
are  the  observations  of  Masius  and  Van  Lair,  who  cut  out 
a  portion  of  the  spinal  cord  in  a  frog,  and  observed  the 
regenerated  tissue  after  the  lapse  of  a  month.  It  con- 
tained apolar,  bipolar,  and  multipolar  cells,  together  with 
"  corpuscles  without  processes,  for  the  most  part  larger 
than  the  cells,  and  appearing  to  be  mere  agglomerations 
of  granules,"  —  these  latter  I  suppose  to  have  been  what 
I  describe  as  segmentations  of  the  undeveloped  sub- 
stance. Gray  fibres,  with  a  few  varicose  fibres,  also 
appeared.* 

140.  Tlie  admirable  investigations  of  Franz  Boll  have 
given  tliese  observations  a  new  significance.  He  finds  in 
the  cerebral  substance  of  the  chick  on  the  third  or  fourth 
day  of  incubation  a  well-marked  separation  between  the 
neuroglia  and  nerve-tissue  joroper.  Fig.  24,  A,  represents 
three  nerve-cells,  each  with  its  nucleus  and  nucleolus,  and 
each  surrounded  with  its  layer  of  neuroplasm.  The  other 
four  masses  he  regards  as  nuclei  of  connective  tissue. 
Three  days  later  tlie  distinction  between  the  two  is  more 
marked  (Fig.  24,  B).  Not  only  liavc  tlic  nerve-cells  ac- 
quired an  increase  of  neuroplasm,  tliey  also  present  indi- 
cations of  their  future  processes,  which  at  tlie  twell'tli  day 

*  Archives  dc  Physiologic,  1872,  p.  268. 
VOL.  III.  13  8 


290  THE    I'lIVSICAL   BASIS    OF   MIND. 

are  varicose  (Fig.  24,  C).  (All  this  while  the  connective 
corpuscles  remain  unchanged.)  Although  Boll  Mas  unable 
to  trace  one  of  these  processes  into  nerve-fibres,  he  has 
little  doubt  that  they  do  ultimately  become  (unite  with  ?) 
axis  cylinders. 

It  is  difficult  to  reconcile  such  observations  with  the 
hypothesis  of  the  cells  being  simply  points  of  reunion  of 
fibrils.  We  see  here  multipolar  cells  before  any  fibrils 
appear.  Eespecting  the  development  of  the  white  sub- 
stance, i.  e.  the  nerve-fibres,  Boll  remarks  that  in  the 
corpus  callosiim  of  the  chick  the  first  differentiation  re- 
sembles that  of  the  gray  substance. 

The  polygonal  and  spindle-shaped  cells  represented  in 
Fig.  25,  A,  are  respectively  starting-points  of  connective 
and  neural  tissues.  The  spindle-shaped  cells  elongate, 
and  rapidly  become  bipolar.  This  is  supposed  to  result 
in  the  whole  cell  becoming  transformed  into  a  fibre,  the 
nucleus  and  nucleolus  vanishing  ;  but  the  transformation 
is  so  rapid  that  he  confesses  that  he  was  unable  to  trace 
its  stages ;  all  that  can  positively  be  asserted  is  that  one 
or  two  days  after  the  appearance  presented  in  Fig.  25,  B, 
the  aspect  changes  to  that  of  fibrils.  The  columns  of 
polygonal  cells  between  which  run  these  fibrils,  he  re- 
gards as  the  connective  corpuscles  described  by  several 
anatomists  in  the  white  substance  both  of  brain  and  cord, 
and  which  are  sometimes  declared  to  be  multipolar  nerve- 
cells.* 

141.  Dr.  Schmidt's  observations  on  the  human  embryo 
were  of  course  on   tissue   at   a  very  much  later  stage. 

*  The  fact  of  the  existence  of  cells  in  the  white  substance  is  one  which 
is  very  difficult  of  interpretation  on  the  current  hypotheses.  The  cells 
are  found  in  regular  columns  and  irregularly  scattered.  Boll  thinks  that 
while  in  the  white  substance  of  both  cerebrum  and  cerebellum  there  are 
trae  nerve-cells  as  well  as  connective  corpuscles,  in  the  cord  there  are  only 
the  latter.  But  hitherto  there  has  been  no  decisive  test  by  which  a  nerve- 
cell  can  be  distinguished  from  a  connective  corpuscle. 


THE   NERVOUS    MECHANISM. 


291 


According  to  him,  the  fibrils  of  the  axis  cylinders  are 
formed  by  the  linear  disposition  and  consolidation  of 
elementary  granules.  The  fibrils  thus  formed  are  sepa- 
rated by  interfibrillar  granules  which  in  time  become  fibrils. 
Not  earlier  than  three  montlis  and  a  half  does  the  forma- 
tion of  individual  axis  cylinders  begin  by  the  aggregation 


Fig.  24.  —  Embryonic  nerve-cells. 


Fig.  25.  —  Embryonic  nerre-fihres. 


292  TIIK    I'llVslCAL   r.ASIS    OF    MIXD. 

of  these   fibrils   into  minute  bundles,  whicli  are  subse- 
quently surrounded  by  a  delicate  slieatb* 

142.  With  resjiect  to  the  transition  ol'  the  spindle- 
shaped  cells  into  librils,  since  there  is  a  gap  in  the  obser- 
vations of  Boll,  and  since  those  of  Schmidt  are  subsequent 
to  the  disappearance  of  the  cells,  and  in  both  cases  all 
trace  of  nucleus  has  disappeared,  I  suggest  that  vre  have 
here  an  analogy  with  what  Weismann  has  recorded  of  the 
metamorphoses  of  insects.  In  the  very  remarkable  me- 
moir of  that  investigator  t  it  is  shown  that  the  metamor- 
phoses do  not  take  place  by  a  gradual  modification  of  the 
existing  organs  and  tissues,  but  by  a  resolution  of  these 
into  their  elements,  and  a  reconstruction  of  their  elements 
into  tissues  and  organs.  The  muscles,  nerves,  trachea?,  and 
alimentary  canal,  undergo  what  may  be  called  a  fatty 
degeneration,  and  pass  thence  into  a  mere  blastema.  It 
is  out  of  these  ruins  of  the  old  tissues  that  the  neiv  tisstics 
are  reconstructed.  On  the  fourth  day  the  body  of  the 
pupa  is  filled  with  a  fluid  mass  —  a  plasma  composed  of 
blood  and  dissolved  tissues.  The  subsequent  develop- 
ment is  thus  in  all  essential  resj)ects  a  repetition  of  that 
which  originally  took  place  in  the  ovum.  I 

*  Monthly  Journal  of  Micros.  Science,  XI.  219.  This  accords  with 
what  KuPFFER  saj-s  respecting  the  entire  absence  of  cells  in  the  earliest 
stages  obser^-ed  by  him  in  the  sheep.  The  Avhite  substance  of  the  spinal 
cord  he  describes  as  soft,  transparent,  and  gelatinous,  in  which  dark 
points  are  visible  ;  these  dark  points  are  seen  in  longitudinal  sections  to 
arise  from  the  fibrillation  of  the  substance.  —  Bidder  und  Kupffer,  Op. 
cit.,  p.  111. 

+  AVeismanx,  Die  nachcrahryonalc  Eniivick.  ckr  Mtcscideji,  in  the  Zcit- 
schrifl  fur  JFissen.  Zoolorjir,  1864,  Bd.  XIV.  Heft  III. 

+  The  suggestion  in  the  text  has  since  received  a  striking  confirmation 
in  the  observations  of  Sigmund  Mayer  on  the  regeneration  of  nerves. 
The  nerve  when  divided  rapidly  undergoes  fatty  degeneration,  which  is 
succeeded  by  a  transformation  of  the  myeline  and  axis  cylinder  into  a 
homogeneous  mass  ;  in  this  resolved  pulp  new  longitudinal  lines  of  divis- 
ion appear,  which  subsefjuently  become  new  fibres,  and  new  nuclei  are 
developed  in  the  remains  of  the  untransformed  substance.  —  Archiv  fur 
Psychiatric,  Bd.  VI.  Heft  II. 


THE  NERVOUS  MECHANISM.  293 

Two  points  are  especially  noticeable  :  First,  that  in  this 
resolved  mass  of  granules  and  fat  globules  there  quickly 
appear  large  globular  masses  which  develop  a  fine  mem- 
brane, and  subsequently  nuclei.  A  glance  at  the  figure 
51  of  Weismann's  plates  reveals  the  close  resemblance  to 
the  earliest  stages  of  nerve-cells ;  and  the  whole  process 
recalls  the  regeneration  of  nerves  and  nerve-centres  after 
their  fatty  degeneration. 

Secondly,  the  nerves  reappear  in  their  proper  places  in 
the  new  muscles,  and  this  at  a  time  when  the  nerve-cen- 
tres are  still  unformed ;  so  that  the  luliole  pcriijhcral  sys- 
tem is  completely  ixhuilt  in  absolute  independence  of  the 
central  system.  The  idea,  therefore,  that  nerve-fibres  are 
the  products  of  ganglia  must  be  relinquished.  This  idea 
is  further  discountenanced  by  Boll's  observations,  which 
show  that  the  fibre-cells  are  from  the  first  different  from 
the  ganglionic  cells ;  and  by  the  observations  of  Foster 
and  Balfour,  that  "  fibres  are  present  in  the  white  sub- 
stance on  the  third  day  of  incubation  "  ;  whereas  cell  pro- 
cesses do  not  appear  until  the  eighth  day.  Foster  and  Bal- 
four are  inclined  to  believe  "  that  even  on  the  seventh 
day  it  is  not  possible  to  trace  any  connection  between  the 
cells  and  fibres."  In  the  later  stages,  the  connection  is 
perhaps  established.* 

*  Strong  confirmation  of  various  statements  in  the  text,  since  they 
were  written,  has  been  furnished  by  the  researclies  of  Eiciihoust,  pub- 
lished in  Virchow's  Archiv,  LXIV.  Our  knowledge  of  the  development 
of  nerve-tissue  in  human  embryos  is  so  scanty  that  these  researches  have 
a  great  value.  Eichuokst  describes  the  striation  of  the  cells  in  the  cord 
to  begin  only  at  the  fourth  month  ;  up  to  this  time  they  are,  what  I  find 
most  invertebrate  cells  to  Ije,  gi-anular,  not  fibrillar.  Theie  is  very  slight 
branching  of  the  cell  processes  until  the  ninth  or  tenth  month,  when  the 
multipolar  aspect  first  appears  ;  the  cells  are  unipolar  up  to  the  end  of 
tiie  fourth  month.  The  connection  between  the  white  columns  and  the 
gray  columns  is  very  loose  up  to  tiie  fifth  mouth  ;  and  tlie  two  are  easily 
separated.  Subseriucntly  the  union  is  closer.  The  substance  of  the  white 
columns  readily  separates  into  bundles  and  fibres,  but  that  of  the  gray 


294  THE  niYSiCAL  basis  of  mind. 

143.  "We  may,  I  think,  conclude  from  all  this  that  in 
the  higher  vertebrates  the  white  substance  of  brain  and 
cord  is  not  the  direct  product  of  the  gray  substance ;  in 
other  words,  that  here  nerve-fibres,  even  if  subsecjuently 
in  connection  with  the  ganglionic  cells,  have  an  inde- 
pendent origin.  They  may  grow  towards  and  blend  with 
cell  processes ;  they  are  not  prolongations  of  those  pro- 
cesses. They  may  be  identical  in  structure  and  property, 
as  one  muscle  is  identical  with  another,  but  one  is  not 
the  parent  of  the  other. 

14-4.  Sigmund  Mayer  emphatically  declares  that  in  no 
instance  has  he  traced  a  cell  process  developed  into  a 
dark-bordered  nerve-fibre.  The  process,  he  says,  may 
often  be  traced  for  a  certain  distance  alongside  of  a  fibre  ; 
but  it  then  suddenly  ceases,  whereas  the  fibre  is  seen  con- 
tinuing its  course  unaltered.  Still  more  conclusive  is  the 
evidence  afforded  by  nerves  having  only  very  few  fibres 
(2-4  sometimes  in  the  frog),  which  have,  nevertlieless, 
a  liberal  supply  of  cells,  visible  without  preparation. 
Valentin  counted  twenty-four  cells  in  a  nerve  M'hich 
had  but  two  fibres.*      Now  although  it  is  possible  to 

columns  falls  into  a  gi-annlar  detritus  if  attempted  to  be  teased  out  with 
needles.  But  after  the  fifth  month  this  is  no  longet  so.  Instead  of  a 
granular  detritus  there  appears  a  network  of  fine  fibres  and  fibrils.  Al- 
though the  white  posterior  columns  are  developed  before  the  fifth  month, 
not  a  single  cell  can  be  seen  in  the  posterior  gray  columns  until  the 
second  half  of  the  ninth  month.  (Yet  the  fibres  are  imagined  to  arise  in 
the  cells !)  The  passage  from  the  granular  to  the  fibrillar  state  is  the 
same  in  the  cell  substance  and  the  neuroglia.  The  nerve-fibre,  as  distin- 
guished from  a  naked  axis  cylinder,  does  not  appear  till  the  fourth  montli. 
It  is  at  first  a  bipolar  prolongation  of  the  nucleus.  As  it  elongates,  the 
nucleus  seems  to  sit  on  it,  and  so  loosely  that  it  is  easily  shifted  away  by 
pressure  on  the  covering  glass.  Finally  the  fibre  separates  entirely  from 
the  nucleus,  and  tJien  begins  to  clothe  itself  with  the  medullary  sheatli. 
Very  curious  is  the  observation  that  so  long  as  the  axis  cylinder  is  naked 
it  is  never  varicose,  but  with  the  development  of  the  medulla  the  primi- 
tive axis  becomes  fluid. 

*  Mayer,  Op.  cit.,  393.     I  cannot,  however,  agree  with  Mayer  when 


THE  NERVOUS  MECHANISM.  295 

explain  the  presence  of  numerous  fibres  with  rare  cells 
either  as  due  to  subdivisions  of  fibres,  or  to  the  fibres 
having  cells  elsewhere  for  their  origin,  it  is  not  thus  that 
Ave  can  explain  the  presence  of  numerous  cells  which 
have  no  fibres  developed  from  their  processes. 

145.  With  regard  to  this  observation  of  the  cell  pro- 
cess running  alongside  of  the  fibre,  the  recent  researches 
of  Eanvier  may  throw  some  light  on  it.  He  describes 
the  cells  in  the  spinal  ganglia  as  all  unipolar;  each  single 
process  pursues  a  more  or  less  winding  course  as  a  fibril, 
often  blending  with  others,  till  it  reaches  one  of  the 
fibres  from  the  sensory  root.  It  blends  with  this  fibre 
at  the  annular  constriction  of  the  fibre,  becoming  liere 
incorporated  with  it,  so  that  a  T-shaped  fibre  is  the  re- 
sult.* If  this  should  be  confirmed,  it  would  reconcile 
many  observations ;  but  it  would  greatly  disturb  all  cur- 
rent interpretations,  llanvier  remarks  that  it  is  no  longer 
tenable  to  suppose  that  the  ganglionic  cell  is  a  centre, 
sensory  or  motor,  receiving  the  excitation  or  sending 
forth  a  motor  impulse  ;  for  if  the  fibril  issuing  from  a 
cell  becomes  laterally  soldered  to  a  nerve-fibre,  there 
is  no  possibility  of  saying  in  which  direction  this  cell 
receives  the  excitation,  nor  in  which  it  transmits  the 
impulse. 

lie  says  that  the  continuity  of  a  nerve-fibre  with  a  cell  has  never  been 
distinctly  shown  (p.  395)  ;  in  the  Invertebrata  and  in  the  Electric  fishes 
such  a  continuity  is  undeniable  ;  and  it  has  occasionally  been  seen  in 
Vertebrata. 

*  Kanvier,  in  the  Comptes  Rendus,  1875,  Vol.  LXXXI.  p.  1270.  This 
observation  throws  light  on  the  fact  that  cell  processes  iuo  soinetiiiics 
seen  entering  nerve-roots  (§  124). 

The  very  remarkable  okservations  of  Mr.  F.  Balfour,  (hi  the  Develop- 
ment of  the  Spinal  Nerves  in  Elasmohranch  Fishes  (Philus.  Trans.,  Vol. 
CLXVI.  p.  1),  show  that  the  spinal  root,  ganglion,  and  nerve-trunk  arise 
from  histologi('!il  changes  in  a  mass  of  cells  at  first  all  alike  ;  not  that 
ganglion-cells  are  formed  and  from  their  jiroccsses  elongate  into  fibres. 
The  nerve,  he  says,  forms  a  continuation  of  its  root  rather  than  of  its 
ganglion  (p.  ISl)  ;  which  aci^ords  with  Hanvi  Kit's  view. 


296  THE  niYsiCAL  basis  of  mind. 

14G.  We  have  seen  good  reason  to  conclude  that  the 
essential  element  of  tlie  nerve  —  the  axis  cylinder  —  is 
the  same  substance  as  the  neuroplasm  which  forms  the 
essential  element  of  the  cell.  At  any  rate,  we  are  quite 
certain  that  the  cell  process  is  neuroplasm.  On  this 
ground  there  is  no  difficulty  in  understanding  that  a  cell 
process  may  sometimes  be  drawn  out  into  an  axis  cylin- 
der (as  indeed  we  see  to  be  the  case  in  the  invertebrata 
and  electric  fishes) ;  while  again  in  numerous  other  cases 
the  nerve-fibre  has  an  independent  origin,  being,  in  short, 
a  differentiation  from  the  neuroplasm  which  has  become  a 
"fibre  instead  of  a  cell.  It  is  clear  from  the  observations 
of  Eouget  on  Development,  and  of  Sigmund  Mayer  on 
Regeneration,  that  fibres,  nuclei,  and  cells  become  differ- 
entiated from  the  same  neuroplasm,  those  portions  which 
are  not  converted  into  fibres  remaining  first  as  lumps  of 
neuroplasm,  then  acquiring  a  nucleus,  and  some  of  these 
passing  into  cells.  I  mean  that  between  fibres,  nuclei, 
and  cells  there  are  only  morphological  differences  in  an 
identical  neuroplasm.*  If  this  is  in  any  degree  true, 
it  will  not  only  explain  how  fresh  fibres  may  be  devel- 
oped in  the  course  of  fibres,  branching  from  them  as 
from  trunks,  and  branchlets  from  branchlets,  twigs  from 
branchlets,  the  same  conditions  of  growth  being  present 
throughout ;  it  will  also  completely  modify  the  notion 
of  any  physiological  distinction  between  cell  and  fibre 
greater  than  can  be  assigned  to  the  morphological  differ- 
ences. We  shall  then  no  longer  suppose  that  the  cell  is 
the  fountain  whence  the  fibre  draws  its  nutrition  and  its 
"  force " ;  and  this  will  be  equally  the  case  even  if  we 
admit  that  a  cell  is,  so  to  speak,  the  germ  from  which 
a  whole  plexus  of  fibres  was  evolved,  for  no  one  will 
pretend  that  the  "  force  "  of  an  organism  is  directly  de- 

*  In  the  I/andbuch  der  menschlichen  jinatomie  of  W.  Krause,  which 
has  just  appeared,  I  am  pleased  to  find  a  similar  view,  p.  376. 


THE  NERVOUS  MECHANISM.  297 

lived  from  the  ovum,  or  that  the  ovum  nourishes  the 
organism. 

147.  At  this  stage  of  the  discussion  it  is  needful  to 
consider  a  point  which  will  spontaneously  occur  to  every 
instructed  reader,  I  mean  the  interesting  i'act  discovered 
by  Dr.  Waller,  that  wlien  a  sensory  root  was  divided,  the 
portion  which  was  still  in  connection  with  the  ganglion 
remained  unaltered,  whereas  the  portion  whicli  was  only 
in  connection  with  the  spinal  cord  degenerated ;  and  vice 
versa,  wdien  a  motor  root  was  divided,  the  portion  con- 
nected with  the  cord  remained  unaltered,  tlie  portion 
severed  from  the  cord  degenerated.  The  observation  has 
been  frequently  confirmed,  and  the  conclusion  drawn  has 
been  that  the  cells  in  the  ganglion  of  the  posterior  root 
are  the  nutritive  centres  of  posterior  nerves,  the  cells  in 
the  anterior  horn  of  the  cord  being  the  nutritive  centres 
of  the  anterior  nerves.  Another  interpretation  is  how- 
ever needed,  the  more  so  because  the  fact  is  not  constant.* 
True  of  some  nerves,  it  is  not  true  of  others.  Yulpian 
found  that  when  he  cut  out  a  portion  of  the  lingual 
nerve,  and  transplanted  it  by  grafting  under  the  skin  of 
the  groin,  where  of  course  it  was  entirely  removed  from 
all  ganglionic  influence,  it  degenerated,  but  it  also  regen- 
erated. Pathological  observations  convinced  Meissner 
that  the  ganglia  are  wholly  destitute  of  an  influence  on 
tlie  nutrition  of  the  vagus  ;    and  Schiff  proved  experi- 

*  On  this  point  consult  Axel  Key  and  Rktzius,  in  the  Jrchiv  fiir 
nxikros.  Anal.,  1873,  p.  308,  where  the  nutritive  disturbance  is  assigned 
to  tlie  fact  that  the  lymph  can  no  longer  take  its  normal  course.  Wal- 
LElt's  oVjservations  on  the  degeneration  of  the  optic  nerves,  with  preserva- 
tion of  the  integrity  of  the  retina,  after  division  of  the  nerves  {Pror.cedimjs 
of  Ilotjfxl  Society,  1856,  p.  10),  cannot  he  urged  in  support  of  his  view, 
because  Beulin  and  Lebeut's  observations  are  directly  contradictory  of 
his.  Sakmisch  und  Giiaefe,  Handbach  dcr  Augenlieilkundc,  II.  346. 
It  is  said  by  KuENCiiEr,  that  if  the  nerves  be  divided,  .so  as  to  prevent 
disturbances  in  the  circulation,  no  peripheral  degeneration  takes  place 
(cit(!d  by  Engel-MANX  in  PJliigers  Archiv,  1875,  p.  477). 
23* 


298  THE   niYSICAL   BASIS   OF   MIND. 

mentally  that  other  ganglia  were  e(|ually  inoperative, 
since  motor  nerves  could  Ije  separated  from  the  Ri)inal 
cord  without  degeneration.*  Not  however  to  insist  on 
this,  nor  on  the  other  facts  of  regeneration,  in  the  ahsence 
of  ganglionic  influence,  let  us  remark  tliat  Dr.  Waller's 
examples  would  not  be  conclusive  unless  the  teaching  ol" 
Embryology  could  be  disproved.  That  nerves  degenerate 
when  separated  from  ganglia  is  a  fact ;  but  it  is  also  a 
fact  that  muscles  degenerate  when  separated  from  a 
nerve-centre ;  yet  we  do  not  suppose  the  nerve-centre 
to  nourish  the  muscles.  And  against  the  fact  that  the 
sensory  nerve  remains  unaltered  only  in  that  portion 
which  is  connected  with  the  ganglion,  we  must  oppose 
the  observations  of  Kolliker  and  Schwalbe,!  wlio  aftirm 
that  none  of  the  fibres  which  enter  the  posterior  columns  ( 
of  the  spinal  cord  have  any  direct  connection  with  the 
cells  of  the  ganglion  on  the  jDosterior  root.  The  cells  of 
this  ganglion  they  declare  to  be  unipolar  (in  the  higher;/ 
vertebrates),  and  the  fibres  in  connection  with  these  cellsj 
are  not  those  which  pass  to  the  cord,  but  all  of  them  pass 
to  the  periphery.  According  to  Eanvier,  the  fibres  from 
the  cells  join  the  fibres  of  the  posterior  root.  Schwalbe 
found  that  if  the  spinal  nerve  be  firmly  grasped  and 
steadily  drawn,  it  will  often  be  pulled  from  its  sheath, 
and  the  ganglion  laid  bare  ;+  in  this  ganglion  all  the  cells 
are  found  undisturbed,  Avhich  could  not  be  the  case  had 
fibres  from  those  cells  entered  the  cord,  since  the  traction 
would  necessarily  have  disturbed  them. 

*  SCHIFF,  Lehrbuch  der  Physiologic,  pp.  120,  121. 

t  Kolliker,  Gewehelchrc,  317.  Schwalbe,  Archivfiir  mikros.  Anat., 
1868,  p.  51. 

X  I  was  first  shown  this  in  1858  by  the  late  Prof.  Haeless  in  Munich, 
who  at  the  same  time  showed  me  that  the  nerve  thus  bared  of  its  sheath, 
if  left  some  hours  in  gastric  juice,  split  up  into  regular  discs,  like  the 
sarcous  elements  of  muscles. 


THE  NERVOUS   MECHANISM.  299 


RECAPITULATION. 

148.  At  the  opening  of  this  chapter  mention  was  made 
of  the  besetting  sin  of  the  analytical  tendency,  namely, 
to  disregard  the  elements  which  provisionally  had  been 
set  aside,  and  not  restore  them  in  the  reconstruction  of 
a  synthetical  explanation.  Familiar  experiences  tell  us 
that  a  stimulus  applied  to  the  skin  is  followed  by  a  mus- 
cular movement,  or  a  glandular  secretion ;  sometimes  this 
takes  place  without  any  conscious  sensation ;  sometimes 
we  are  distinctly  conscious  of  the  stimulus ;  and  some- 
times we  consciously  will  the  movement.  These  facts  the 
physiologist  tries  to  unravel,  and  to  trace  the  complicated 
processes  involved.  The  neurologist  of  course  confines 
himself  exclusively  to  the  neural  processes  ;  all  the  other 
processes  are  provisionally  left  out  of  account.  But 
not  only  so :  the  analytical  tendency  is  carried  further, 
and  even  in  the  neural  process  the  organs  are  neglected 
for  the  sake  of  tlie  nervous  tissue,  and  the  nervous  tis- 
sue for  the  sake  of  the  ncrvc-cell.  The  consequence  has 
been  that  we  have  an  explanation  offered  us  which  runs 
thus : — 

149.  The  nerve-cell  is  the  supreme  element,  the  origin 
(jf  the  nerve-fibre,  and  the  fountain  of  nerve-force.  The 
cells  are  connected  one  with  another  by  means  of  fibres, 
and  with  muscles,  glands,  and  centres  also  by  means  of 
fibres,  which  are  merely  channels  for  the  nerve-force.  A 
stimulus  at  tlie  surface  is  carried  by  a  sensory  fibre  to  a  cell 
in  the  centre ;  from  that  point  it  is  carried  l)y  another 
fibre  to  another  cell ;  and  from  that  by  a  third  fibre  to  a 
muscle :  a  reflex  contraction  results.  This  is  the  elemen- 
tary "  nervous  arc."  But  this  arc  has  also  higher  arcs 
with  which  it  is  in  connection :  the  sen.sory  cell  besides 
sending  a  fibre  directly  to  a  motor  cell,  also  sends  one 
upwards  to  the  cerebral  centres ;  and  here  again  there  is 


300  THE   PHYSICAL   BASIS   OF   MIND. 

a  nervous  arc,  so  that  the  cerebral  centre  sends  down 
an  impulse  on  the  motor  cells,  and  the  contraction  which 
results  is  due  to  a  volitional  impulse.  The  transmission 
of  the  stimulation  which  in  the  first  case  was  purely 
physical,  becomes  in  the  latter  case  psychical.  The  sen- 
sory impression  is  in  one  cell  transformed  into  a  sensa- 
tion, in  another  cell  into  an  idea,  in  a  third  cell  into  a 
rolitioji. 

150.  This  course  is  described  with  a  precision  and  a 
confidence  which  induces  the  inexperienced  reader  to  sup- 
pose that  it  is  tlie  transcript  of  actual  observation.  1 
venture  to  say  that  it  is  imagmary  from  beginning  to  end. 
I  do  not  affirm  that  no  such  course  is  pursued,  I  only  say 
no  such  course  was  ever  demonstrated,  but  that  at  every 
stage  the  requisite  facts  of  observation  are  either  incom- 
plete or  contradictory.  First,  be  it  noted  that  the  actions 
to  be  explained  are  never  the  actions  of  organs  so  simple 
as  the  description  sets  forth.  It  is  not  by  single  fibres 
and  cells  that  the  stimulus  is  effected,  but  by  complex 
nerves  and  complex  centres.  Only  by  a  diagrammatic 
artifice  can  the  fibre  represent  the  nerve,  and  the  cell  the 
centre.  In  reality  the  cells  of  the  centre  (supposing  them 
to  be  the  onli/  agents)  act  in  groups,  and  Anatomy  should 
therefore  show  them  to  be  mutually  united  in  groups  — 
which  is  what  no  Anatomy  has  succeeded  in  showing, 
unless  the  Neuroglia  be  called  upon.  Secondly,  be  it 
noted  that  the  current  scheme  of  the  relations  between 
cells  and  fibres  is  one  founded  on  physiological  postulates, 
not  on  observation.  Thirdly,  much  of  what  is  actually 
observed  is  very  doubtful,  because  we  do  not  know 
whether  the  appearances  are  normal,  or  due  to  modes 
of  preparation  and  post-mortem  changes.  We  cannot  at 
present  say,  for  instance,  whether  the  fibrillated  appear- 
ance of  cell  contents  and  axis  cylinder  represents  the  liv- 
ing structure  or  not.     We  may  either  suppose  that  the 


THE  NERVOUS  MECHANISM.  301 

neuroplasmic  pulp  splits  longitudinally  into  fibres,  or  that 
neuroplasmic  threads  resolve  themselves  into  a  homo- 
geneous pulp  —  the  axis  cylinder  may  be  a  condensation 
of  many  fibrils,  or  the  fibrils  may  be  a  resolution  of  the 
substance. 

151.  Let  us  contrast  step  by  step  the  Imaginary  Anat- 
omy found  in  the  text-books  with  the  Objective  Anatomy 
as  at  present  disclosed  by  the  researches  of  all  the  chief 
workers.  Imaginary  Anatomy  assumes  that  the  sensory 
fibre  passes  from  a  surface  into  the  cells  of  the  posterior 
horn  of  the  spinal  cord.  Objective  Anatomy  sees  the 
fibre  pass  into  the  gray  substance,  but  declares  that  no 
direct  entrance  of  a  fibre  into  a  cell  is  there  visible. 

Imaginary  Anatom.y  assumes  that  from  the  sensory 
cells  of  the  gray  substance  pass  fibres  in  connection  with 
the  motor  cells  of  the  anterior  horn,  thus  forming  a  direct 
channel  through  which  the  excitation  of  a  sensory  cell  is 
transmitted  to  a  motor  cell.  Objective  Anatomy  fails 
to  discover  any  such  direct  channel  —  no  such  fibres  are 
demonstrable. 

Imaginary  Anatomy  assumes  that  from  the  motor  cells 
issue  fibres  which  descend  to  the  muscles  and  glands,  and 
carry  there  the  motor  impulses  and  tlie  "  mandates  of  the 
will."  Objective  Anatomy  fails  to  find  at  the  utmost 
more  than  a  probability  that  these  cells  are  continued  as 
fibres,  a  probability  whicli  is  founded  on  the  rare  facts 
of  cell  processes  having  been  seen  extending  into  the 
roots  of  the  nerves,  and  of  a  cell  process  having  occa- 
sionally been  seen  elsewhere  continuous  with  a  dark- 
bordered  fibre.  Granting,  liowever,  tliat  this  probability 
represents  the  fact,  we  have  tlius  only  one  part  of  tlie 
"nervous  arc"  which  can  be  said  to  have  been  verified. 

Imaginary  Anatomy  further  assumes  that  this  nervous 
arc  is  connected  with  cerebral  centres  by  means  of  fibres 
going  upwards  from  the  posterior  cells,  and  fibres  descend- 


302  THE   PHYSICAL  BASIS  OF   MIND. 

ing  downwards  to  the  anterior  cells.  Objective  Anatomy- 
sees  nothing  of  the  kind.  It  sees  fibres  entering  the  gray 
substance,  and  there  lost  to  view  in  a  mass  of  granular 
substance,  fibrils,  neuroblasts,  and  cells.  There  may  he 
uninterrupted  fibres  passing  upwards  and  downwards ; 
but  it  is  impossible  to  see  them.  And  if  we  are  told  that 
physiological  interpretations  demand  such  a  structure, 
we  may  fairly  ask  if  this,  and  this  only,  is  the  struc- 
ture which  is  adequate  to  the  propagation  of  excitation  ? 
Now  it  seems  to  me  that  another  kind  of  structure,  and 
one  more  closely  agreeing  with  what  is  observed,  better 
answers  the  demands  of  Physiology.  This  will  be  more 
evident  after  the  Laws  of  Nervous  Action  have  been  ex- 
pounded in  the  succeeding  chapter.  Meanwhile  we  may 
remark  that  the  arrangement  of  cells  and  fibres  which  is 
imagined  as  the  mechanism  of  propagation  and  reflexion 
is  absolutely  irreconcilable  with  the  teaching  of  Experi- 
ment :  for  the  spinal  cord  may  be  cut  through  anywherej 
without  destruction  of  the  transmission  of  sensory  and 
motor  excitations,  provided  only  a  small  portion  of  gray 
substance  be  left  to  establish  the  continuity  of  the  axis. 
Divide  all  the  substance  of  the  posterior  half  in  one 
place,  and  all  the  substance  of  the  anterior  half  in  an- 
other, yet  so  long  as  there  is  a  portion  of  gray  substance 
left  as  a  bridge  between  the  lower  and  upper  segments, 
the  transmissiou  of  sensory  and  motor  excitations  will 
take  place. 

152.  In  other  essential  respects  we  have  to  note  that 
the  anatomical  evidence  for  the  current  interpretations  is 
absolutely  deficient  or  contradictory.  There  is  no  ade- 
(l^uate  warrant  for  the  assumption  that  all  nerves  have 
their  origin  in  ganglia,  all  fibres  in  cells.  Such  evidence 
as  at  present  exists  is  against  that  supposition,  and  in 
favor  of  the  supposition  that  both  cell  and  fibre  are  dif- 
ferentiations of  a  common  neuroplasm,  sometimes  directly, 


THE  NERVOUS  MECHANISM.  303 

sometimes  indirectly  continuous.  Fibres,  and  plexuses  of 
fibres,  interspersed  with  cells  irregularly  distributed  — 
now  singly,  now  in  small  groups,  now  in  larger  and 
larger  groups  —  constitute  the  figured  elements  of  nerve- 
tissue  ;  and  even  if  we  set  aside  the  amorplious  substance 
as  indifferent  or  subordinate,  we  have  still  no  ground  for 
assigning  the  supremacy,  much  less  the  sole  significance, 
to  the  cells.  The  grounds  of  this  denial  have  been  amply 
furnished  in  our  exposition.  For,  let  it  be  granted  that 
nerve-cells  are  the  origins  of  the  fibres  and  the  sources  of 
their  nutrition  —  a  point  which  is  eminently  disputable  — 
this  would  in  no  sense  help  the  physiological  hypothesis 
of  the  cell  as  the  fountain  of  Neurility.  If  the  fibre  is 
simply  the  cell-contents  drawn  out  longitudinally,  if  its 
essential  element  is  identical  with  the  essential  element 
of  the  cell,  then  we  can  no  more  ascribe  to  the  cell  the 
exclusive  property  of  Neurility  than  we  can  draw  a  lump 
of  lead  out  into  a  wire,  and  then  ascribe  different  prop- 
erties to  the  thin  end  and  the  thick  end.  But  on  this 
point  it  is  needless  to  speculate,  since  we  have  experi- 
mental evidence  proving  that  tlie  nerve-fibre  has  its  Neu- 
rility even  when  separated  from  the  cell,  or  even  from  the 
ganglion. 

153.  It  is  possible  —  I  do  not  see  sufficient  evidence 
for  a  stronger  assertion  —  tliat  the  cells  are  the  nutri- 
tive sources  of  the  fibres.  They  may  represent  the  ali- 
mental  rather  than  the  instrumental  activities  of  nervous 
life.  (Compare  Problem  I.  §  42.)  My  contention  is 
that  in  any  case  tliey  are  not  the  su])reme  elements  of 
the  active  tissue,  and  in  no  sense  can  they  be  considered 
as  organs.  Only  confusion  of  ideas  could  for  a  moment 
permit  sucli  language,  or  could  assign  central  functions  to 
cells  wliicli  are  elements  of  tissue.  If  the  cell  be  cred- 
ited witli  such  powers  anywhere,  it  must  be  credited  with 
them  everywhere.     Now  I  ask  wliat  conceivable  central 


304  THE  PHYSICAL  basis  of  mind. 

function  can  be  ascribed  to  a  cell  which  terminates  the 
fibre  in  a  peripheral  ganglion,  or  which  is  merely  an  en- 
larsement  in  the  course  of  a  fibre  in  a  nerve-bundle  ? 
Besides  the  facts  already  adduced,  let  attention  be  called 
to  this :  If  a  nerve-bundle  from  the  siihniucusa  of  the  in- 
testine be  examined,  there  appear  among  the  fibres  many 
nuclei  (neuroblasts),  and  occasionally  cells,  unipolar  and 
bipolar.  These  cells  —  if  we  may  trust  the  observations 
of  liouget  on  the  earliest  development  of  nerves,  and  of 
Sigmund  Mayer  on  regenerated  nerves  —  are  simply  more 
advanced  stages  of  evolution  of  the  neuroblasts  ;  but  what- 
ever their  genesis  mav  be,  there  can  be  nothing  in  the 
nature  of  a  central  function  assigned  to  them. 

154.  It  may  be  asked,  "What  part  can  we  assign  to 
cells  in  neural  actions  if  they  are  apolar,  unipolar,  and 
even  when  multipolar,  isolated  from  each  other,  and  from 
fibres  ?  I  confess  that  I  have  no  answer  ready,  not  even 
an  hypothesis.  Until  some  rational  interpretation  of  the 
cell  be  given  we  must  be  content  to  hold  an  answer  in 
suspense.  "What  I  would  urge  is  that  we  are  precipitate 
in  assuming  that  the  anatomical  connection  between  one 
element  and  another  must  necessarily  be  that  of  a  fibre. 
In  a  semi-fluid  substance,  such  as  neurine,  continuity  may 
be  perfect  without  solid  fibres :  the  amorphous  substance 
and  the  plasmode  may  as  well  transmit  waves  of  molecu- 
lar motion  from  one  part  of  the  tissue  to  another,  and 
therefore  from  cell  to  cell,  or  from  cell  to  fibre,  as  a 
figured  substance  may.  When  the  posterior  root  enters 
the  gray  substance  of  the  cord,  there  is  no  more  necessity 
for  its  fibres  passing  directly  into  the  cells  of  that  gray  sub- 
stance, in  order  to  excite  their  activity,  than  there  is  for  a 
wire  to  pass  from  the  bell  to  the  ear  of  the  servant,  who 
hears  the  vibrations  of  the  bell  through  the  pulsations  of 
the  intervening  air  upon  her  tympanum.  Look  at  the 
structure  of  the  retina,  or  the  cerebellum,  and  you  will 


THE  NERVOUS  MECHANISM.  305 

find  that  the  ganglionic  cells  which  have  processes  pass- 
ing in  a  direction  contrary  to  that  whence  the  stimulus 
arrives,  have  none  where  continuity  of  fibre  and  cell 
would  be  indispensable  on  the  current  hypothesis.  Light 
stimulates  the  rods  and  cones,  but  there  are  no  nerve- 
fibres,  hitherto  discovered,  passing  from  these  to  the  gan- 
glionic cells ;  instead  of  that  there  is  a  ground-substance 
thickly  interspersed  with  granules  and  nuclei.  From  the 
cells  we  see  processes  issue ;  to  the  cells  none  are  seen 
arriving.  So  with  the  cerebellum.  The  large  cells  send 
their  processes  upwards  to  the  surface;  but  downwards 
towards  the  white  substance  the  processes  are  lost  in  the 
granular  layer,  which  most  histologists  regard  as  connec- 
tive tissue. 

155.  A  mere  glance  at  nervous  tissue  in  any  part  will 
show  that  cells  are  far  from  forming  the  principal  constit- 
uents. In  the  epidermis  or  a  gland  the  cell  is  obviously 
tlie  chief  element,  forming  the  bulk  of  the  tissue,  and 
being  the  characteristic  agent.  In  nerve-tissue,  as  in 
connective  tissue,  the  reverse  is  the  case.  We  must 
therefore  cease  to  regard  the  cell  as  having  the  impor- 
tance now  attached  to  it,  and  must  rather  throw  the 
emphasis  on  the  fibres  and  neuroglia. 

156.  Before  quitting  this  subject  let  a  word  be  said  on 
the  amazing  classification  wliich  has  attained  wide  accept- 
ance (although  rejected  by  the  most  eminent  authorities), 
founded  on  the  size  of  the  cells  —  the  large  nmltipolar 
cells  being  specified  as  motor,  the  smaller  cells  as  sensory, 
while  those  of  an  intermediate  size  are  sympathetic.  I 
forbear  to  dwell  on  the  development  of  this  notion  which 
specifies  sensational,  ideational,  and  emotional  cells,  be- 
cau.se  this  does  not  pretend  to  have  a  basis  in  observation  ; 
whereas  there  are  anatomical  facts  which  give  a  certain 
superficial  plausi))ility  to  the  original  classification.  The 
conception  is  profoundly  unphysiological ;  yet,  if  the  ana- 


306  THE  PHYSICAL  BASIS   OF   MIND. 

tomical  evidence  were  constant,  one  might  give  it  another 
interpretation.  The  evidence  is,  however,  not  constant. 
Large  cells  are  found  in  regions  assigned  to  sensory  nerves, 
and  small  cells  in  motor  regions.  In  the  spinal  cord  of 
the  tortoise  Stieda  declares  that  the  so-called  motor  cells 
are  limited  to  the  cervical  and  lumbar  enlargements ;  all 
the  rest  of  the  motor  region  being  absolutely  destitute  of 
them.*  Again  look  at  the  cells  of  the  retina  —  no  one 
will  assign  motor  functions  to  them  —  yet  they  are  the 
same  as  those  of  the  cerebellum  and  the  anterior  horns  of 
the  spinal  cord.  (It  is  worth  a  passing  mention  that  the 
structure  of  the  nervous  parts  of  the  retina  more  closely 
resembles  that  of  the  cerebellum  than  of  the  cerebrum.) 

157.  While  our  knowledge  of  the  cell  is  thus  far  indeed 
from  having  the  precision  which  the  text-books  display, 
and  in  no  sense  warrants  the  current  physiological  inter- 
pretations, our  knowledge  of  fibres  and  neuroglia  is  also 
too  incomplete  for  theoretic  purposes.  We  know  that 
the  axis  cylinder  is  the  essential  element ;  but  we  are 
stiU  at  a  loss  what  part  is  to  be  assigned  to  the  medullary 
sheath.  There  is  indeed  a  popular  hypothesis  which  pro- 
nounces it  to  be  the  means  of  insulating  the  fibre,  and 
thus  preserving  the  isolated  conduction  of  nerve-force. 
Being  of  a  fatty  nature,  this  insulating  office  was  readily 
suggested  in  agreement  with  the  assumption  that  ISTeuril- 
ity  was  Electricity.  Now,  w^ithout  discussing  whether 
Neurihty  is  or  is  not  Electricity,  even  admitting  the 
former  to  be  satisfactorily  proved,  I  must  remark  that  the 
admission  still  leaves  the  medullary  sheath  incapable  of 
fulfilling  the  supposed  office,  since  not  only  is  there  no 
such  sheath  in  most  of  the  invertebrates  and  in  the  sym- 
pathetic ner\'es  of  vertebrates,  but  even  in  those  nerves 
which  have  the  sheath  it  is  precisely  in  places  w^here  the 

*  Stieda,  Bau  des  centralen  Neroensystem  der  AmpMbien  und  Reptilien, 
1875,  p.  41. 


THE  NERVOUS  MECHANISM.  307 

insulation  would  be  most  needed  —  namely,  just  before 
the  terminations  of  the  fibres  in  muscles  and  in  centres  — 
that  the  sheath  is  absent.  This  is  as  if  we  tried  to  con- 
duct water  through  a  pipe  which  fell  short  at  both  ends  — 
before  it  left  the  cistern,  and  before  it  reached  the  spot  to 
be  watered.  If  there  is  a  tendency  in  Neurility  to  spread 
wherever  it  is  not  insulated  by  a  medullary  sheath,  then 
before  reaching  the  centres  and  the  muscles,  it  nmst,  on 
the  insulating  hypothesis,  dribble  away  ! 

158.  The  facts  expressed  in  the  "law  of  isolated  con- 
duction "  are  important,  and  are  difhcult  of  explanation ; 
but  it  is  obvious  that  they  cannot  be  referred  to  the  pres- 
ence of  the  medullary  sheath.  Xor  indeed  will  any  in- 
sight into  the  propagation  of  stimulation  through  the 
central  axis  be  intelligible  until  we  have  reformed  our 
anatomical  theories,  and  taken  the  Neuroglia  into  account. 
The  theory  which  connects  every  fibre  directly  with  a  cell, 
and  every  cell  with  another  by  anastomosis  —  even  Avere 
it  demonstrated  —  would  not  explain  tlie  law  of  isolated 
conduction.  Butzke  cogently  remarks  *  that  such  a  dis- 
position of  tlie  elements  should  render  all  neural  paths 
invariable ;  whereas  the  fact  is  that  tliey  are  very  varia- 
ble. We  learn  to  perform  actions,  and  then  we  unlearn 
tliem ;  the  paths  are  traversed  now  in  one  direction,  now 
in  another.  Fluctuation  is  the  characteristic  of  central 
combinations.  And  for  this  fluctuating  combination  of 
elements  a  corresponding  diversity  is  required  in  the  pos- 
sible channels.  This  seems  to  be  furnished  by  the  net- 
work of  tlie  Neuroglia.  See  the  representation  copied 
from  Butzke's  plate,  and  note  how  the  cell-process  blends 
with  the  meshes  of  the  Neuroglia.  Is  it  fanciful  to  regard 
tliis  network  of  flbrils  as  having  somewhat  the  relation  of 
capillaries  to  blood-vessels  ?     iJid  we  not  experimentally 

*  Butzke,  in  Arcldv  fur  mikroslcojnsclic  Anatomic,  Bd.  III.  I  left  3, 
p.  596. 


308 


THE    rilYSICAL   BASIS   OF   MIND. 


know  that  the  capillaries  are  terminal  hlood-vessels,  we 
sliould  not  suspect  it  from  mere  examination  of  the 
structure. 

159.  Having  insisted  that  our  knowledge  is  insufficient 
for  any  explanation  of  the  "  law  of  isolated  conduction,"  I 
can  only  suggest  a  path  of  research  which  may  lead  to 
some  result.  What  we  know  is  that  some  stimulations 
are  propagated  from  one  end  of  the  cerebro-spinal  axis  to 
the  other  in  definitely  restricted  paths,  while  others  are 


Fig.  26. —  Nerve-cells  with  processes  terminating  in  neuroglia. 

irradiated  along  many  paths.  In  the  succeeding  chapter 
this  will  be  more  fully  considered ;  what  we  have  here  to 
note  is  that  the  manifold  irradiations  of  a  stimulation 
have  an  anatomical  substratum  in  the  manifold  sub- 
divisions of  the  network  of  fibrils  and  the  amorphous 
substance  in  which  they  penetrate. 

160.  In  conclusion,  I  would  say,  let  no  one  place  a  too 
great  confidence  in  the  reigning  doctrines  respecting  the 
elementary  structure  of  the  nervous  system,  but  accept 
every  statement  as  a  "working  hypothesis"  which  has 
its  value  in  so  far  as  it  links  together  verified  facts,  or 


THE  NERVOUS  MECHANISM.  309 

suggests  new  researcli,  but  is  wholly  without  value  in  so 
far  as  it  is  made  a  basis  of  deductions  not  otherwise 
verified.  Hypotheses  are  indispensable  to  research,  but 
they  must  be  accompanied  by  vigilant  scepticism.  Imagi- 
nation is  only  an  enemy  to  Science  when  Scepticism  is 
asleep. 


310  THE  niYsicAL  basis  of  mind. 


CHAPTEE    VIII. 

THE  LAWS   OF   NERVOUS   ACTIVITY. 

161.  The  foregoing  remarks  have  bad  tlie  object  of 
sbowiDg  bow  bttle  substantial  aid  Psycbology  can  at 
present  derive  from  wbat  is  known  of  the  elementary 
structure  of  the  nervous  system,  indispensable  as  an  ac- 
curate knowledge  of  that  structure  must  be  to  a  com- 
plete analysis  of  its  functions.  This  caution  has  been 
specially  addressed  to  those  medical  and  psychological 
students  whose  researches  leave  them  insufficient  leisure 
to  pursue  microscopical  investigations  for  themselves,  and 
who  are  therefore  forced  to  rely  on  second-hand  knowl- 
edge, which  is  usually  defective  in  the  many  qualify- 
ing considerations  which  keep  scepticism  vigilant.  Eely- 
ing  on  positive  statements,  and  delusive  diagrams  which 
only  display  what  the  observer  imagines,  not  what  he 
actually  sees,  the}''  construct  on  such  data  theories  of  dis- 
ease, or  of  mental  processes ;  or  else  they  translate  ob- 
served facts  into  tlie  terms  of  this  imaginary  anatomy, 
and  offer  the  translation  as  a  new  contribution  to  Science. 

162.  But  little  aid  as  can  at  present  be  derived  from 
the  teaching  of  the  microscope,  some  aid  Psychology  may 
even  now  derive  from  it.  The  teaching  will  often  serve, 
for  instance,  to  correct  the  precipitate  conclusions  of 
subjective  analysis,  which  present  artificial  distinctions 
as  real  distinctions,  separating  what  Nature  has  united. 
It  will  show  certain  organic  connections  not  previously 
suspected ;  and  since  whatever  is  organically  connected 


THE  NERVOUS  MECHANISM.  311 

cannot  functionally  be  separated,  such  sharply  marked 
analytical  distinctions  as  those  of  periphery  and  centre, 
or  of  sensation  and  motion,  must  be  only  regarded  as 
artificial  aids.  The  demonstration  of  the  indissoluble 
union  of  the  tissues  is  a  demonstration  of  their  functional 
co-operation.  So  also  the  anatomical  demonstration  of 
the  similarity  and  continuity  of  all  parts  of  the  central 
system  sets  aside  the  analytical  separation  of  one  centre 
from  another,  except  as  a  convenient  artifice ;  proving 
that  cerebral  substance  is  one  with  spinal  substance, 
having  the  same  properties,  the  same  laws  of  action. 

For  the  present.  Psychology  must  seek  objective  aid 
from  Physiology  and  Pathology  rather  than  from  ele- 
mentary Anatomy.  In  the  paragraphs  which  are  to  fol- 
low I  shall  endeavor  to  select  the  chief  laws  of  nervous 
activity  which  the  researches  of  physiologists  and  patholo- 
gists disclose.  By  these  laws  we  may  direct  and  control 
psychological  research. 

THE   ENERGY   OF   NEURILITY. 

163.  Vitality  is  characterized  by  incessant  molecular 
movement,  both  of  composition  and  decomposition,  in 
tlie  building  up  of  structure  and  the  liberation  of  energy. 
The  life  of  every  organism  is  a  complex  of  changes,  each 
of  which  directly  or  indirectly  affects  the  statical  and 
dynamical  relations,  each  being  the  resultant  of  many 
co-operant  forces.  In  the  nourishment  of  every  organite 
there  is  an  accumulation  of  molecular  teiiKion,  that  is 
to  say,  stored-up  energy  in  a  latent  state,  ready  to  be 
expended  in  the  activity  of  that  organite ;  and  this  ex- 
penditure may  take  place  in  a  steady  flow,  or  in  a  sud- 
den gush.  The  molecular  movements  under  one  aspect 
may  be  called  convergent,  or  forviativc:  they  liuild  the 
structure,  and  tend  to  the  state  of  equilibrium  which 


:U2  THE  PHYSICAL  BASIS   OF   MIND. 

■\ve  call  the  statical  condition  of  tlic  organite,  i.  e.  the 
condition  in  Mliich  it  is  not  active,  but  ready  to  act. 
Perfect  equilibrium  is  of  course  never  attained,  owing 
to  the  incessant  molecular  change :  indeed  Life  is  incon- 
sistent -with  complete  repose.  Under  another  aspect  the 
molecular  movements  may  be  called  di>ic]iar(jin<j :  they 
constitute  the  dynamic  condition  of  the  organite,  in  which 
its  functional  activity  appears.  The  energy  is  now  di- 
verted, liberated,  and  the  surplus,  over  and  above  that 
which  is  absorbed  in  formation,  instead  of  slowly  drib- 
bling off,  gushes  forth  in  a  directed  stream.  The  slow 
formation  of  a  secretion  in  a  gland-cell,  and  the  discharge 
of  that  secretion,  will  illustrate  this ;  or  (if  muscular  tone 
be  admitted)  the  incipient  contraction  of  the  chronic 
state,  and  the  complete  contraction  of  the  dynamic  state,' 
may  also  be  cited. 

164.  The  discharge  which  follows  excitation  may  thus 
be  view'ed  as  a  directed  quantity  of  molecular  movement. 
Because  it  is  always  strictly  relative  to  the  energy  of 
tension,  and  is  inevitable  ^vhen  that  tension  attains  a 
certain  surplus  over  what  is  required  in  construction, 
there  is  a  limit,  1°,  to  the  growth  and  evolution  of  every 
organite,  and  every  organism  (comp.  Problem  I.  §  118), 
and,  2°,  to  its  dynamical  effect.  When  there  is  no  sur- 
fdns,  the  organite  is  incapable  of  discharge :  it  is  then 
exhausted,  i.  e.  will  not  respond  to  stimulus. 

165.  The  speciality  of  nerve-tissue  is  its  pre-eminence 
in  directive  energy.  Like  all  other  tissues,  it  grows,  de- 
velops, and  dies ;  but  above  all  others  it  has  what  we  call 
excitahility,  or  readiness  in  discharging  its  energy  in  a 
directed  stream.  By  its  topographical  distribution  it 
plays  the  functional  part  of  exciting  the  activity  of  other 
tissues :  it  transmits  molecular  disturbance  from  periph- 
ery to  centre,  from  centre  to  centre,  and  from  centre 
to  muscles,  vessels,   and   glands.      When   a    muscle  is 


THE  NERVOUS  MECHANISM.  813 

excited  it  moves,  and  when  a  gland  is  excited  it  secretes ; 
but  these  actions  end,  so  to  speak,  with  themselves; 
the  muscle  does  not  directly  move  any  other  muscle;'* 
the  gland  does  not  directly  excite  any  other  gland.  The 
nerve,  on  the  contrary,  has  always  a  wide-spreading  effect ; 
it  excites  a  centre  which  is  continuous  with  other  cen- 
tres ;  and  in  exciting  one  muscle,  usually  excites  a 
group.  Hence  the  nervous  system  is  that  u-liiclt  hinds 
the  different  orgeins  into  a  elynamic  tinity.  And  Compara- 
tive Anatomy  teaches  that  there  is  a  parallelism  between 
the  development  of  this  system  and  the  efficient  com- 
plexity of  the  oi'ganism.  As  the  tissues  become  more 
and  more  specialized,  and  the  organs  more  and  more  indi- 
vidualized, they  would  become  more  and  more  unsuited 
to  the  general  service  of  the  organism,  were  it  not  tliat  a 
corresponding  development  of  the  nervous  system  brought 
a  unifying  mechanism. 

The  great  instability  of  neurine,  in  other  w'ords,  its 
high  degree  of  tension,  renders  it  especially  apt  to  dis- 
turb the  tension  of  other  .tissues.  It  is  very  variable; 
and  this  variability  will  have  to  be  taken  into  account 
in  explaining  the  restriction  of  discharges  to  particular 
centres.  A  good  example  of  exaggerated  tension  is  fur- 
nished by  strychnine  poisoning.  The  centres  are  then 
so  readily  excitable  that  a  touch,  or  a  puff  of  cold  air  on 

*  Except  in  the  rare  cases  where  there  is  anastomosis  of  the  muscle- 
fibres  ;  as,  for  example,  in  the  heart.  [According  to  ExoiiLMANN's 
lernarkable  researches,  the  muscles  of  the  heart  form  a  continuum,  so  that 
iiritation  is  propagated  from  ojie  to  the  otlier :  Pflugcrs  Archiv,  1875, 
]).  46.5.  Tliis  is  indnhitahly  the  case  in  the  embryonic  heart,  as  EcK- 
ii.vi'.i)  pointed  out.]  Tliis  I  hold  to  be  the  main  cause  of  its  rhythmic 
pulsation  after  removal  from  tlic  body.  Whatever  influence  the  ganglia 
m.'iy  have  in  exciting  this  pulsation,  such  influence  would  be  powerless 
were  not  the  muschis  so  connected  ;  as  may  be  seen  in  the  other  organs 
wliich  are  richly  sujjplied  with  ganglia,  yet  ilo  not  move  spontaneously  ; 
and  in  organs  (such  as  the  ureter  or  the  embryonic  heart,  and  the  hearts 
of  invertebrata)  which  move  spontaneously,  yet  have  no  ganglia, 

voT,.   II r,  14 


314  THE    PHYSICAL   BASIS   OF    MIND. 

the  skin,  will  determine  convulsions.  And  it  is  wortliy 
of  remark  that  for  some  hours  after  this  convulsive  dis- 
charge the  centres  return  to  something  like  their  normal 
state;  and  the  animal  may  then  be  stroked,  yjinched, 
or  blown  upon  without  abnormal  reactions.  But  during 
this  interval  the  centres  are  slowly  accumulating  excess 
of  tension  from  the  poisoned  blood  ;  and  at  the  close,  con- 
vulsions will  again  follow  the  slightest  stimulus.  This 
alternation  of  exhaustion  and  recrudescence  is  noticed 
by  Schroder  van  der  Kolk  in  the  periodicity  of  the  phe- 
nomena exhibited  in  spinal  disease.* 

THE    PROPAGATION    OF   EXCITATION. 

166.  Understanding,  then,  that  the  propagation  of  an 
excitation  depends  on  the  state  of  tension  of  the  tissue, 
and  always  follows  the  line  of  least  resistance,  whichever 
that  may  be  at  the  moment,  we  have  to  inquire  whether 
the  transmission  takes  place  only  in  one  direction,  from 
periphery  to  centre  in  sensory  nerves,  and  from  centre  to 
periphery  in  motor  nerves  ?  "By  most  physiologists  this 
is  answered  affirmatively.  Indeed  a  special  property  has 
been  assigned  to  each  nerve,  in  virtue  of  this  imaginary 
limitation  of  centripetal  and  caatrifugal  conduction.  The 
"  nerve-current "  (accepted  as  a  physical  fact,  and  not  sim- 
ply a  metaphor)  is  supposed  to  "  flow "  from  the  central 
cells  along  the  motor  nerve  to  the  muscles ;  but  by  a 
strange  oversight  the  current  is  also  made  to  "  flow  "  to- 
ivards  the  central  cells  which  are  said  to  produce  it !  Now 
although  the  fact  may  be,  and  probably  is,  that  normally 
the  sensory  nerve,  being  stimulated  at  its  peripheral  end, 
propagates  the  stimulation  towards  the  centre,  and  the 
motor  nerve  propagates  its  central  stimulation  towards  the 
periphery,  the  question  whether  each  nerve  is  not  capable 

*  Schroder  van  der  Kolk,  Bau  und  FunJctionen  der  Med.  Sphialis, 
p.  67. 


THE  NERVOUS  MECHANISM.  315 

of  transmission  in  both  directions  is  not  thus  answered. 
A  ijriori  it  is  irrational  to  assert  that  nerves  fundamen- 
tally alike  in  composition  and  structure  are  unlike  in  prop- 
erties ;  and  we  might  as  well  suppose  that  a  train  of 
gunpowder  could  only  be  fired  at  one  end,  as  to  suppose 
that  a  nerve  could  only  be  excited  at  one  end.  And  how 
does  the  evidence  support  this  a  priori  conclusion  ?  Du- 
bois Eeymond  proved  that  each  nerve  conducted  elec- 
tricity in  both  directions ;  but  as  Neurility  has  not  been 
satisfactorily  shown  to  be  identical  with  the  electric  cur- 
rent, this  may  not  be  considered  decisive.  Such  a  doubt 
does  not  hang  over  the  following  facts.  M.  Paul  Bert, 
pursuing  John  Hunter's  curious  experiments  on  animal 
ffrafting,  has  grafted  the  tail  of  a  rat  under  the  skin  of 
the  rat's  back,  the  tip  of  the  tail  being  inserted  under  the 
skin,  its  base  rising  into  the  air,  so  that  there  is  here  an 
inversion  of  the  normal  position.  In  the  course  of  time 
Sensibility  gradually  reappears  in  this  grafted  tail ;  and  at 
the  end  of  about  twelve  months  the  rat  not  only  feels 
when  the  tail  is  pinched,  but  knows  where  the  irritation 
lies,  and  turns  round  to  bite  the  pincers.*  Here  we  have 
a  c'ise  of  a  sensory  nerve  reversed,  yet  transmitting  stim- 
idation  from  the  base  to  the  tip  of  the  tail,  instead  of  from 
the  tip  to  the  base,  as  in  a  normal  organ.  Vulpian  and 
Philippeaux  having  divided  two  nerves,  united  the  central 
end  of  the  sensory  nerve  with  the  peripheral  end  of  the 
motor  nerve ;  when  the  organic  union  was  complete,  and 
each  nerve  was  formed  out  of  the  halves  of  two  different 
nerves,  the  effect  of  pinching  one  of  these  was  to  produce 
simultaneously  pain  and  movement,  showing  that  the  ex- 
citation was  transn)itt(!d  upwards  to  tlie  centre,  and  down- 
wards to  the  muscles.f     It  may  be  compared  witli  a  train 

*  It  is  very  instructive  to  learn  that  for  some  six  montlis  or  so  the  rat 
is  fjuite  incapable  of  correctly  lorMizing  the  pain. 
t  VuLi'iAN,  Lemons  sur  Ic  Systeme  Nervciu;  p.  2S8.     The  expi-iinient 


316  THE   rilVSICAL   BASIS   or   MIND. 

oi"  gunpowder  having  a  loaded  cannon  at  one  end  and  a 
Ijundle  of  straw  at  the  other,  when  if  a  spark  be  dropped 
anywhere  on  this  train,  the  flame  runs  along  in  Loth  direc- 
tions, explodes  the  cannon,  and  sets  alight  the  straw. 

1G7.  Indeed  we  have  only  to  remember  the  semi-liquid 
nature  of  the  axis  cylinder  to  see  at  once  that  it  must  con- 
duct a  wave  of  motion  as  readily  in  one  direction  as  in 
another.  A  liquid  transmits  waves  in  any  direction  ac- 
cording to  the  initial  impulse.  There  is  consequently  no 
reason  for  asserting  that  because  the  usual  direction  i.s 
centripetal  in  a  sensory  nerve,  and  centrifugal  in  a  motor 
nerve,  each  nerve  is  incapable  of  transmitting  excitations 
in  both  directions.  And  I  think  many  phenomena  are 
more  intelligible  on  the  assumption  that  neural  transmis- 
sion is  in  both  directions.  If  the  eye  is  fixed  steadfastly 
on  a  particular  color  during  some  minutes,  the  retina  be- 
comes exhausted,  and  no  longer  responds  to  the  stimulus 
of  that  color :  here  the  stimulation  is  of  course  centripe- 
tal. But  if  instead  of  looking  intently  on  the  color,  the 
mind  (in  complete  absence  of  light)  pictures  it  intenilj^ 
tJiis  cerebral  image  is  equally  capable  of  exhausting  the  l^t- 
ina ;  and  nnless  we  believe  that  color  is  a  cerebral,  rjot 
a  retinal  phenomenon  (which  is  my  private  opinion),  vve 
must  accept  this  as  proof  of  a  centrifugal  excitation  of  a 
sensory  tract.  Another  illustration  may  be  drawn  from 
the  muscular  sense.  There  may  be  a  few  sensory  fibres 
distributed  to  muscles ;  but  even  if  the  observations  of 
Sachs*  should  be  confirmed,  I  do  not  think  that  all  mus- 
cle sensations  can  be  assigned  to  these  fibres,  but  that  the 
so-called  motor  fibres  must  also  co-operate.    "When  a  nerve 

has  been  confirmed  bj'  Rosenthal,  and  by  Bidder  (Archiv  fur  Ana- 
tomic, I860,  p.  246),  who  first  (in  1842)  attempted  this  union  of  different 
nerves,  but  arrived  at  negative  results  ;  as  did  Schiff  {Lchrbttch  der 
PhjfsioL,  1859,  p.  134)  and  Gluge  et  Thieexes.se  {AmiaJes  des  Sciences 
Katurclles,  1859,  p.  181). 

*  S.XCHS,  in  the  Archiv  fiir  Anat.,  1874,  pp.  195,  sq. 


THE   NERVOUS    MECHANISM.  317 

acts  upon  a  muscle,  the  muscle  reacts  on  the  nerve  ;  and 
when  a  nerve  acts  on  a  centre,  the  centre  reacts  on  the 
nerve.  The  agitation  of  the  central  tissue  cannot  leave 
tlie  nerve  which  blends  with  it  unatlected ;  the  agitation 
of  the  muscular  tissue  must  also  by  a  reversal  of  the 
"  current "  affect  its  nerve.  Laplace  points  out  how  tlie 
movement  of  the  hand  which  holds  a  suspended  chain  is 
propagated  along  the  chain  to  its  terminus,  and  if  when 
the  chain  is  at  rest  we  once  more  set  that  terminus  in 
motion,  the  vibration  will  remount  to  the  hand.*  The 
contraction  of  a  muscle  will  not  only  stimulate  the  sen- 
sory fibres  distributed  through  it,  but  also,  I  conceive, 
stimulate  the  very  motor  fibres  whicli  caused  the  contrac- 
tion, since  these  fibres  blend  with  the  muscle,  f 

168.  To  understand  this,  it  is  necessary  to  remember 
that  the  stimulation  of  a  nerve  does  not  arise  j  in  the 
changed  state  of  that  nerve,  but  in  the  process  of  change, 
i.  e.  the  disturbance  of  the  tension.  The  duration  of  the 
stimulation  is  that  of  the  changing  process,  and  the  in- 
tensity increases  with  the  differential  of  the  velocity  of 
change.  So  that  when  a  nerve  which  has  been  excited 
by  a  change  of  state  returns  to  its  former  state,  this  return 
—  being  another  change  —  is  a  new  excitation.     That  it 


*  Laplace,  Essai  Philos.  sur  Ics  Probabilitc'/i,  p.  239. 

t  The  mode  of  termination  of  nerve.s  in  muscles  is  still  a  point  on 
which  histologists  disagree  ;  probably  because  there  is  no  abrupt  termi- 
nation, but  a  blending  of  the  one  tissue  with  the  other.  In  the  Tardi- 
grades,  for  example,  there  is  actually  no  appreciable  distinction  between 
nerve  and  muscle  at  the  point  of  insertion  of  the  nerve  ;  and  if  in  the 
liigher  animals  there  is  an  appreciabli;  dilference  between  nerve  and  mus- 
cle, there  is  an  inseparable  blending  of  undilfcrentiated  substance  at  their 
j)oint  of  junction.  [According  to  Knckl.mann's  recent  researches,  there 
seems  good  reason  to  suppose  that  muscles  are  compo.sed  of  contractile 
substance  and  a  substance  wliich  is  a  modification  of  axis-cylinder  sub- 
stance ;  the  first  being  doubly  refracting,  the  .second  isotropic :  PJliigcrs 
Archiv,  1875,  p.  432.] 

X  Sen  IFF,  Lchrbuch,  p.  73. 


318  THE  niYsicAL  basis  of  mind. 

is  not  the  changed  state,  but  the  change,  which  is  opera- 
tive, explains  the  fact  noted  by  Brown  Sequard :  a  frog 
poisoned  by  strychnine,  wlien  decapitated  and  all  respira- 
tion destroyed,  will  remain  motionless  for  days  together, 
if  carefully  protected  from  all  external  excitation  ;  but  its 
nervous  system  is  in  such  a  state  of  tension  all  this  time 
that  the  fir^  touch  produces  general  convulsions.  Freus- 
berg  also  notes  that  if  a  brainless  frog  be  suspended  by 
the  lower  jaw,  and  one  foot  be  pinched,  the  other  leg  is 
moved  at  first,  then  quickly  droops  again,  and  remains  at 
rest  until  the  pincers  are  removed  from  the  pinched  foot, 
when  suddenly  all  four  legs  are  violently  moved  by  the 
stimidation  ivhich  the  simjjle  removal  produces.  Let  us 
also  add  the  well-known  and  significant  fact  that  if  a 
nerve  be  divided  rapidly  by  a  sharp  razor,  neither  sensa- 
tion nor  motion  is  produced,  because  the  intensity  of  a 
stimulus  being,  to  speak  mathematically,  the  function  of 
the  changing  jJ^'ocess,  the  duration  of  the  process  is  in  this 
case  too  brief.  On  the  same  ground  the  application  of  a 
stimulus  will  excite  no  movement,  if  the  force  be  very 
slowly  increased  from  zero  to  an  intensity  which  will  de- 
stroy the  nerve ;  but  at  any  stage  a  sudden  increase  will 
excite  a  movement. 

169.  We  may  group  all  the  foregoing  considerations  in 
this  formula : 

Law  I.  Every  neural  process  is  due  to  a  sudden  dis- 
turbance of  the  molecular  tension.  The  liberated 
energy  is  discharged  along  the  lines  of  least  re- 
sistance. 

The  conditions  which  determine  the  lines  of  least  resist- 
ance are  manifold  and  variable.  The  nervous  system  is  a 
continuous  whole,  each  part  of  which  is  connected  with 
diverse  organs ;  but  in  spite  of  this  anatomical  diversity, 
the  deeper  uniformity  causes  the  activity  of  each  part  to 
depend  on  and  involve  the  activity  of  every  other,  more 


THE  NERVOUS   MECHANISM.  31*J 

or  less.  By  "  more  or  less  "  is  meant,  that  although  the 
excitation  of  one  pai't  necessarily  affects  the  state  of  all 
the  others,  because  of  their  structural  community,  so  that 
each  sensation  and  eacJi  motion  really  represents  a  change 
in  the  ivhole  organism,  yet  the  responsive  discharge  deter- 
mined in  each  organ  by  this  change,  depends  on  the  ten- 
sion of  the  organ  and  its  centre  at  that  moment.  A  bad 
harvest  really  affects  the  whole  nation ;  but  its  effect  is 
conspicuous  on  the  welfare  of  the  poor  rather  than  of  the 
rich,  although  the  price  of  bread  is  the  same  to  rich  and 
poor.  Nervous  centres,  and  muscular  or  glandular  organs, 
differ  in  their  excitability ;  one  condition  of  this  greater 
excitability  being  the  greater  frequency  with  which  they 
are  called  into  activity.  The  medulla  oblongata  is  nor- 
mally more  excitable  than  the  medulla  spinalis  ;  the  lieart 
more  than  the  limbs.  Hence  a  stimulus  wliich  will  in- 
crease the  respiration  and  the  pulse  may  have  no  appreci- 
able effect  on  the  limbs ;  but  some  effect  it  must  have. 

170.  Imagine  all  the  nerve-centres  to  be  a  connected 
group  of  bells  varying  in  size.  Every  agitation  of  the 
connecting  wire  will  more  or  less  agitate  all  the  bells ; 
but  since  some  are  heavier  than  others,  and  some  of  th(^ 
cranks  less  movable,  there  will  be  many  vibrations  of 
the  wire  whicli  will  cause  some  bells  to  sound,  otliers 
simply  to  oscillate  without  sounding,  and  others  not  sen- 
sibly to  oscillate.  Even  some  of  the  lighter  bells  will  not 
ring  if  any  external  pressure  arrests  them  ;  or  if  they  are 
already  ringing,  the  added  impulses,  not  being  rhythmically 
timed,  will  arrest  the  ringing.  So  tlie  stimulus  of  a  sen- 
sory nerve  agitates  its  centre,  and  tlirough  it  the  whole 
system ;  usually  the  stimulation  is  mainly  reflected  on 
the  group  of  muscles  innervated  from  that  centre,  because 
this  is  the  readiest  path  of  discharge ;  but  it  sometimes 
does  not  mainly  discharge  along  this  path,  the  line  of  least 
resistance  lying  in  another  direction  ;  and  the  discharge 


320  THE   rilYSlCAL   BASIS   OF   MIND, 

never  takes  this  path  without  also  irradiating  upwards 
and  downwards  through  the  central  tissue.  Thus  irradi- 
ated, it  falls  into  the  general  stream  of  neural  processes ; 
and  according  to  the  state  in  which  the  various  centres 
are  at  the  moment  it  modifies  their  activity.  A  nervous 
shock  —  physical  or  mental  —  sensibly  affects  all  the  or- 
gans. A  severe  wound  paralyzes,  for  a  time,  parts  far 
removed  from  the  wounded  spot.  A  blow  on  the  stomach 
will  arrest  the  heart ;  a  fright  will  do  the  same.  Terror 
relaxes  the  limbs,  or  sets  them  trembling ;  so  does  a  con- 
cussion :  if  a  frog  be  thrown  violently  on  the  ground,  all 
its  muscles  are  convulsed ;  but  if  the  nerves  of  one  limb 
l)e  divided  before  the  shock,  the  muscles  of  that  limb  will 
not  be  convulsed. 

171.  We  are  apt  to  regard  the  discharge  on  the  moving 
organs  as  if  that  were  the  sole  response  of  a  stimulation ; 
but  although  the  most  conspicuous,  it  is  by  no  means 
the  most  important  effect.  Besides  exciting  the  muscles, 
more  or  less,  every  neural  process  has  its  influence  on  the 
organic  processes  of  secretion,  and  effects  thermal  and 
electrical  changes.  SchifF  has  demonstrated  that  every 
sensation  raises  the  temperature  of  the  brain ;  Nothnagel, 
that  irritation  of  a  sensory  nerve  causes  constriction  of 
the  cerebral  arteries,  and  hence  cerebral  ansemia.  Brown 
Sdquard  and  Lombard  find  the  temperature  of  a  limb 
raised  when  its  skin  is  pinched,  and  lowered  when  the 
skin  elsewhere  is  pinched.  Georges  Pouchet  has  shown  that 
fishes  change  color  according  to  the  brightness  or  dark- 
ness of  the  ground  over  which  they  remain ;  and  these 
changes  are  dependent  on  nervous  stimulation,  mainly 
through  the  eye,  division  of  the  optic  nerves  preventing 
the  change.  These  are  so  many  a  posteriori  confirmations 
of  what  a  priori  may  be  foreseen.  They  are  cited  here 
merely  to  enforce  the  consideration,  seldom  adequately 
kept  before  the  mind,  that  every  neural  process  is  a  change 
which  causes  other  chan<]ces  in  the  whole  organism. 


THE   NERVOUS   MECHANISM.  321 


STIMULI. 

172.  Stimuli  are  classed  as  external  and  internal,  or 
physical  and  physiological.  The  one  class  comprises  all 
the  agencies  in  the  External  Medium  whicli  ajjjjrcctahl// 
affect  the  organism ;  the  other  class  all  the  changes  in  the 
organism  M'hich  appreciably  disturb  the  equilibrium  of 
any  organ.  Although  the  pressure  of  the  atmosphere, 
for  example,  unquestionably  affects  the  organism,  and 
determines  organic  processes,  it  is  not  reckoned  as  a  stim- 
ulus unless  the  effect  become  appreciable  under  sudden 
variations  of  the  pressure.  In  like  manner  the  blood  is 
not  reckoned  among  the  internal  stimuli,  except  when 
sudden  variations  in  its  composition,  or  its  circulation, 
determine  appreciable  changes.  Because  the  external 
stimuli,  and  the  so-called  Senses  which  respond  to  them, 
are  more  conspicuous  than  the  internal  stimuli  and  the 
Systemic  Senses,  they  have  unfortunately  usurped  too 
much  attention.  The  massive  influence  of  the  Systemic 
Sensations  in  determining  the  desires,  volitions,  and  con- 
ceptions of  mankind  has  not  been  adequately  recognized. 
Yet  every  one  knows  the  effect  of  impure  air,  or  a  con- 
gested liver,  in  swaying  the  mental  mood ;  and  how  a 
heavy  meal  interferes  with  muscular  and  mental  exer- 
tion.* What  is  conspicuous  in  such  marked  effects,  is 
less  conspicuously,  but  not  less  necessarily,  present  in 
slighter  stimuli. 

173.  A  constant  pressure  on  the  tympanum  excites  no 
sound ;  only  a  rhythmic  alternation  of  pressures  will  ex- 
cite the  sensation.     A  constant  temperature  is  not  felt ; 

*  Fi;i",T-snF-uo  observed  tliat  tin!  reflex  tiiovcrncnts  in  the  l('j:;,s  of  a  dog 
wlios(!  spine  hail  been  divided  were  coiisideral)!)'  lessened  after  food  or 
drink.  They  fell  from  95  to  40  pendulum-beats  in  a  ininiite  after  a  /Ure 
of  water  liad  been  drunk.  See  liis  instructive  memoir,  Reflex- Ldhniim- 
gcn  beim  Ilundc,  in  Pfliirjcrs  Archie,  1874,  p.  309. 

14*  u 


322  THE  PHYSICAL  BASIS   OF  MIND. 

only  changes  in  temperature.  If  Liglit  and  Sound  were 
as  nniibrni  as  the  circulation  of  the  l)loo(l,  or  the  pressure 
of  the  atmosphere,  we  should  be  seldom  conscious  of  the 
existence  of  these  stimuli.  But  because  the  changes  are 
varied  and  marked,  our  attention  is  necessarily  arrested 
by  them.  The  changes  going  on  within  the  tissues  are 
too  graduated  to  fix  the  attention  ;  it  is  only  by  consider- 
ing their  cumulative  effects  that  we  become  impressed 
with  their  importance.  For  example,  the  development 
of  the  sexual  glands  determines  conspicuous  physical  and 
moral  results  —  we  note  consequent  effects  on  voice,  hair, 
horns,  structure  of  the  skull  and  size  of  the  muscles,  no 
less  than  the  rise  of  new  feelings,  desires,  instincts,  ideas. 
Any  organic  interference  with  the  activity  of  the  ovaries 
will  alter  the  moral  disposition  of  the  animal:  suppression 
of  this  organic  process  means  non- development  of  the 
feelings  of  maternity ;  the  moral  superstructure  is  absent 
because  its  physical  basis  is  wanting. 

174.  Blood  supplies  the  tissues  with  their  plasmodes ; 
a  constant  supply  of  oxygenated  blood  is  therefore  neces- 
sary to  the  vitality  of  the  tissues.  But  it  is  an  error  to 
suppose  that  oxygen  is  the  special  stimulus  of  nerve- 
centres,  or  that  their  activity  depends  on  their  oxidation  ; 
on  the  contrary,  the  deficiency  of  oxygen  or  surj)lus  of 
carbonic  acid  is  that  which  stimulates.  "When  saturated 
with  oxygen,  the  blood  paralyzes  respiration ;  when  some 
of  the  oxygen  is  withdrawn,  respiration  revives.  Here  — 
as  in  all  other  cases  —  we  have  to  remember  that  differ- 
ences in  degree  readily  pass  into  differences  in  kind,  so 
that  an  excess  of  a  stimulus  produces  a  reversal  of  the 
effect;  thus  although  surplus  of  carbonic  acid  excites 
respiratory  movements,  excess  of  carbonic  acid  causes 
Asphyxia.  Abundance  of  blood  is  requisite  for  the  con- 
tinuous activity  of  nerve-centres ;  but  while  a  temporary 
deficiency  of  blood  renders  them  more  excitable,  too  great 


THE  NERVOUS  MECHANISM.  323 

a  deficiency  paralyzes  them.  Anaemia,  which  causes  great 
excitability,  and  convulsions  (so  that  nerves  when  dying 
are  most  irritable),  may  easily  become  the  cause  of  the 
death  of  the  tissue.  There  are  substances  which  can  only 
be  dissolved  by  a  given  quantity  of  liquid ;  if  this  quan- 
tity be  in  excess,  they  are  precipitated  from  the  solution. 
There  are  vibrations  of  a  given  order  which  cause  each 
string  to  respond ;  change  the  special  order,  and  the 
string  returns  to  its  repose. 

In  the  stillness  and  darkness  of  the  night  we  are  ex- 
cluded from  most  of  the  external  stimuli,  yet  a  massive 
stream  of  systemic  sensations  keeps  the  sensitive  mechan- 
ism active,  and  in  sleep  directs  the  dreams.  The  cramps 
and  epileptiform  attacks  which  occur  during  sleep  are 
most  probably  due  to  the  over-excitability  produced  by 
surplus  carbonic  acid.  To  temporary  anaemia  may  be 
assigned  the  strange  exaggeration  of  our  sensations  dur- 
ing the  moments  which  precede  awakening;  and  the 
greater  vividness  of  dream-images. 

It  is  only  needful  to  mention  in  passing  the  varied 
stimuli  by  which  cerebral  changes  act  upon  the  organism. 
The  mention  of  a  name  will  cause  a  blush,  a  brightening 
of  the  eye,  a  quickening  of  the  pulse.  The  thought  of 
her  absent  infant  will  cause  a  flow  of  milk  in  the  mother's 
breast. 

175.  We  may  formulate  the  foregoing  considerations  in 
another  law : 

Law  TI.  The  neural  excitation,  which  is  itself  a  change, 
directly  causes  a  change  in  the  organ  innervated, 
and  indirectly  in  tlie  wliolc  organism. 

The  significance  of  this  law  is,  that  although  for  the 
convenience  of  research  and  exposition  we  isolate  one 
organ  from  the  rest  of  the  organism,  and  one  process  from 
all  the  co-operant  processes,  wo  liave  to  remember  that 
this  is  an  artifice,  and  tliat  in  reality  there  is  no  such 
separation. 


324  THE  PHYSICAL  BASIS   OF  MIND. 


STIMULATION. 

176.  Passing  now  from  these  general  considerations  to 
their  special  application,  we  may  formulate  the  law  of 
stimulation : 

Law  III.  A  faint  or  moderate  stimulation  increases  the 
activity  of  the  organ ;  but  beyond  a  certain  limit, 
increase   of    stimulation   diminishes,   and   finally 
arrests,  the  activity.     Duration  of  stimulation  is 
equivalent  to  increase. 
A  muscle  stimulated  contracts ;  if  the  stimulation  be 
repeated,  the  muscle  becomes  tetanized,  and  in  this  state 
has  reached  its  limit ;  a  fresh  stimulation  then  relaxes  the 
muscle.     A  very  faint  stimulation  of  the  vagus  quickens 
the  pulsation  of  the  heart,  but  a  slight  increase,  or  dura- 
tion of  the  stimulation,  slackens  and  arrests  the  heart.* 
Every  one  knows  how  a  moderate  feeling  of   surprise, 
pleasure,  or  pain  quickens  the  heart  and  the  respiration ; 
and  how  a  shock  of  surprise,  joy,  grief,  or  great  physical 

*  !RI.  Herzex  thus  describes  the  effects  of  stimulating  the  vagus  with 
varying  intensities:  "Si  Ton  se  sert  de  I'appareil  de  Dubois  Reymond, 
on  commence  par  appliquer  une  initation  tellement  faible  qu'elle  ne 
produit  aucun  effet ;  on  rapproche  alors  peu  a  peu  les  deux  bobines  de 
I'appareil  avec  le  plus  gi'and  soin,  par  fractions  de  centimetres,  par  onilli- 
mltres  s'il  le  faut,  et  Ton  trouve  ainsi  le  degi-e  d'irritation  qui  accelere  les 
battements  du  cceur  et  qui  pi'oduit  le  maximum  de  pulsations  dans  I'unite 
de  temps  admise  pour  I'experience.  Quand  on  est  Ih,  il  suffit  d'un  milli- 
metre de  plus  pour  faire  disparaitre  I'augmentatio:),  un  autre  millimetre 
peut  produire  une  diminution,  et  un  troisieme  pent  arreter  le  coeur  com- 
pletement.  En  reculant  alors,  en  eloignant  peu  a  peu  les  deux  bobines,  on 
retmirne  a  la  force  qui  2)roduit  V augmentation  des  battements."  Hekzen, 
Experiences  sur  les  Centres  Modirateurs  de  V Action  Rejlcxe,  1864,  p.  68. 
There  have  been  serious  doubts  thrown  on  these  experiments  ;  but  sev- 
eral experimenters  have  confirmed  their  exactness.  Quite  recently  they 
have  been  confirmed  by  Bulgheri,  E  Morgagni,  VIII.  ;  and  by  Arlo- 
ING  and  Tripier,  Areliivcs  cZc  Physiologic,  1872,  IV.  p,  418.  It  must  be 
confessed,  however,  that  the  whole  subject  of  the  heart's  innervation  is 
at  present  very  imperfectly  understood. 


THE  NERVOUS  MECHANISM.  325 

pain  depresses,  and  even  arrests  them.     Excess  of  light  is 
blinding ;  excess  of  sound  deafening. 

177.  The  nervous  system  is  incessantly  stimulated, 
and  variably.  Hence  a  great  variation  in  the  excita- 
bility of  different  parts.  AVliile  the  regular  and  mod- 
erate activity  of  one  part  is  accompanied  by  a  regular 
How  of  blood  to  it,  so  that  there  is  a  tolerably  constant 
rhythm  of  nutrition  and  discharge,  any  irregular  or  ex- 
cessive activity  exhausts  it,  until  there  has  been  a  nu- 
tritive restoration.  We  can  thus  understand  how  one 
centre  may  be  temporarily  exhausted  while  a  neighbor- 
ing centre  is  vigorous.  Cayrade  decapitated  a  frog,  and 
suspended  light  weights  to  each  of  its  hind  legs ;  when 
either  leg  was  stimulated,  the  weight  attached  to  it  was 
raised.  After  each  repetition  the  weight  was  raised  less 
and  less,  until  finally  the  weight  ceased  to  be  raised : 
the  centre  had  been  exhausted.  But  now  when  the  other 
leg,  which  had  been  in  repose,  was  stimulated,  it  ener- 
getically contracted,  and  raised  its  attached  weight ;  show- 
ing that  its  centre  was  not  exhausted  by  the  action  of  the 
other.* 

178.  This  seems  in  contradiction  with  the  principle 
that  the  excitation  of  one  centre  is  an  excitation  of  all. 
It  also  seems  in  contradiction  with  the  principle  urged 
by  Ilerzen,  that  irritation  of  one  sciatic  nerve  diminishes 
the  excitability  of  the  opposite  leg ;  and  this  again  seems 
contradicted  by  tlie  principle  urged  by  Setschenow,  that 
althougli  moderate  excitation  of  one  sciatic  nerve  will 
diminish  the  excitability  of  the  other,  a  powerful  excita- 
tion will  increase  it. 

179.  All  three  principles  are,  I  believe,  exact  expres- 
sions of  experimental  evidence;  and  their  seeming  con- 
tradictions may  be  reconciled  on  a  wider  survey  of  the 
laws  of  neural  activity,  interpreted  according  to  the  spe- 

*  Caykade,  LecJicrchcs  sur  les  MouvemeTits  Rijlexes,  1864,  p.  58. 


326  THE   PHYSICAL   BASIS    OF   MIND. 

cial  conditions  of  each  case.  These  laws  may  be  con- 
veniently classified  as  Laws  of  Discharge,  and  Laws  of 
Arrest ;  the  second  being  only  a  jiarticular  aspect  of  the 
first. 

THE   LAW   OF   DISCHARGE. 

180.  The  physiological  independence  of  organs,  to- 
gether with  their  intimate  dependence  in  the  organism, 
and  the  fact  that  this  organism  is  incessantly  stimulated 
from  many  sides  at  once,  assure  us  a  loriori  that  the 
"  waves "  of  molecular  movement  due  to  each  stimulus 
must  sometimes  interfere  and  sometimes  blend  with 
others,  thus  diverting  or  neutralizing  the  iinal  discharge 
in  the  one  case,  and  in  the  other  case  swelling  the  cur- 
rent and  increasing  the  energy  of  the  discharge.  We 
are  accustomed  to  speak  of  one  part  "playing  on  another," 
sympathizing  with  another,  and  so  on ;  but  what  is  the 
process  expressed  in  these  metaphors  ?  When  an  idea, 
or  a  painful  sensation,  quickens  the  pulse,  or  increases 
the  flow  of  a  secretion,  w^e  are  not  to  imagine  that  from 
a  spot  in  the  cerebrum,  or  the  surface,  there  is  a  nerve- 
fibre  going  directly  to  the  heart,  or  the  gland,  transmit- 
ting an  impulse ;  in  each  case  the  central  tissue  has 
been  agitated  by  a  sudden  change  at  the  stimulated  point, 
and  the  discharge  on  heart  and  gland  is  the  resultant  of 
this  agitation  along  the  lines  of  least  resistance.  The 
nerves  of  the  great  toe,  for  example,  pass  into  the  spinal 
cord  at  a  considerable  distance  from  the  spot  where  the 
nerves  of  the  arm  enter  it;  when,  therefore,  the  great 
toe  is  pinched,  the  arm  does  not  move  by  direct  stimula- 
tion of  its  nerves,  but  by  the  indirect  stimulation  which 
has  traversed  the  whole  central  substance. 

181.  This  is  intelligible  when  w^e  know  that  the  whole 
central  substance  is  continuous  throughout ;  but  the  dif- 
ficulty arises  when  we  have  to  explain  why,  if  this  cen- 


THE   Is'ERVOUS   MECHANISM.  327 

tral  substance  is  stimulated  throughout,  only  arms  and 
legs  respond ;  in  other  words,  why  the  toe-centre  "  plays 
upon "  the  arm-centre,  and  not  on  the  others  ?  When 
a  frog  is  decapitated,  if  we  gently  touch  one  leg  with 
the  point  of  the  scalpel,  the  leg  will  move,  but  only  this 
leg.  Prick  more  forcibly,  and  both  legs  will  move. 
Keep  on  pricking,  and  all  four  legs  are  drawn  up,  and 
the  frog  hops  away.  Each  excitation  was  propagated 
along  the  cord ;  but  the  discharge  was  restricted  in  the 
first  case  to  one  limb,  in  the  second  to  two,  in  the  third 
it  involved  all  the  muscles  of  the  trunk.  At  the  sight  of 
a  friend  a  dog  wags  his  tail  gently :  as  there  is  no  direct 
connection  between  the  optic  nerves  and  the  tail,  this 
playing  of  one  centre  on  another  must  be  by  the  agency 
of  intermediate  centres ;  and  we  know  that  if  the  dog's 
spinal  cord  be  divided,  this  excitation  from  the  optic 
centre  is  no  longer  possible,  yet  the  tail  will  wag  if  the 
abdomen  be  tickled,  or  the  leg  pinched.  Now  compare 
the  effect  on  the  dog  produced  by  the  sight  of  his  master, 
or  of  a  friend  accustomed  to  take  him  out.  There  is  no 
longer  a  gentle  wagging  of  the  tail,  but  an  agitation  of 
the  whole  body :  he  barks,  leaps,  and  runs  about ;  the 
central  stimulation  is  discharged  through  many  outlets ; 
and  could  we  test  the  effect,  we  sliould  find  an  appre- 
ciable alteration  in  the  thermal  and  electrical  condition 
of  the  whole  organism,  with  corresponding  changes  in 
circulation,  secretion,  etc.  So  different  are  the  conse- 
quences of  two  slightly  different  retinal  impressions 
mingling  their  stimulations  with  the  same  mass  of  central 
substance ! 

182.  The  discharge  is  determined  by  two  conditions: 
the  state  of  tension,  and  tlic  energy  of  the  stimulation. 
The  stale  of  tension  is  increased  hy  every  stimulation  which 
frills  short  of  a  discharge ;  tliat  is  to  say,  faint  and  fre- 
quent  stimulation    augments    the    excitability,   whereas 


o2S  THE   niYSICAL   BASIS   OF  MIND. 

powerful  stimulation  exhausts  it.  "Wlien,  therefore,  one 
wave  succeeds  another  in  the  same  direction,  it  reaches 
a  centre  more  disposed  to  discharge ;  or,  as  Cayrade  ex- 
presses it,  "a  certain  agitation  of  the  cells  is  necessary 
for  the  manifestation  of  their  property  of  reaction,  in 
the  same  way  that  the  concentric  circles  produced  on 
the  surface  of  water  by  a  falling  stone  are  more  rapid  and 
more  numerous  if  a  stone  has  already  agitated  the  sur- 
face." 

183.  So  much  for  the  tension.  AVhat  has  been  called 
the  energy  of  the  stimulation  is  more  complicated.  It  is 
not  measurable  as  a  simple  physical  process ;  we  cannot 
say  that  a  given  quantity  of  any  external  force  will  de- 
termine a  given  discharge.  It  is  mostly  complicated  by 
psychical  processes,  and  these  so  modify  the  result  that 
instead  of  the  predicted  discharge  there  is  arrest,  or  dis- 
charge from  another  centre.  Press  a  dog's  skin  with 
increasing  violence,  and  the  effect  increases  from  pleas- 
urable to  painful  irritation ;  but  whether  the  dog  will 
cry  out  and  bite,  or  cry  out  and  struggle  to  escape,  de- 
pends upon  whether  the  pincher  is  a  stranger  or  a  friend. 
If  you  hurt  a  dog  while  removing  a  thorn  from  its  foot 
it  will  cry  out,  but  although  the  pain  causes  it  to  initiate 
a  biting  movement,  by  the  time  your  hand  is  reached 
that  movement  will  have  been  changed,  and  the  dog 
^vill  lick  the  hand  which  he  knows  is  hurting  him  in  the 
endeavor  to  relieve  him  of  the  thorn.  The  co-oi^eration 
of  the  mind  is  here  evident  enough.  A  purely  psychical 
process  has  interfered  with  the  purely  physiological 
process.  And  I  shall  hereafter  endeavor  to  show  that 
psychical  processes  analogous  in  kind  though  simpler  in 
degree  are  really  co-operant  in  actions  of  the  spinal  cord. 
The  dog  would  be  said  to  discriminate  between  the  pain 
inilicted  by  a  friend,  and  the  same  pain  inflicted  by  a 
stranger.     In  other  M'ords,  the  sensitive  mechanism  would 


THE  NERVOUS  MECHANISM.  329 

be  differently  determined  in  the  direction  of  discharge, 
although  the  initial  stimulation  was  the  same  in  each 
case.  If  we  admit  that  the  resulting  action  is  in  each 
case  the  consequence  of  the  particular  group  of  elements 
co-operating,  there  will  be  no  ground  for  denying  that 
analogous  discrimination  is  manifested  by  the  brainless 
animal,  who  also  responds  differently  to  different  external 
stimuli,  and  differently  to  the  same  stimulus  under  dif- 
ferent central  conditions.  The  brainless  frog  croaks  if 
its  back  be  gently  stroked  with  the  handle  of  a  scalpel ; 
but  if  the  point  be  used,  or  if  the  handle  be  roughly 
pressed,  instead  of  croaking,  the  frog  raises  his  leg  in 
defence.  Here  the  difference  in  the  peripheral  irrita- 
tion has  excited  a  different  reaction  in  the  centre ;  and 
tliis  might  be  interpreted  as  purely  physical ;  if  now  the 
leg  be  fastened,  and  the  movement  of  defence  be  thus 
prevented,  the  frog  will  employ  the  other  leg;  or  adopt 
some  other  means  of  relieving  itself  from  tlie  irritation. 
It  Avas  a  mass  of  registered  experiences  which  deter- 
mined the  dog  not  to  bite  his  master.  An  analogous 
registration  of  experiences  determines  the  changed  reac- 
tions of  the  brainless  frog.  But  this  is  a  point  which 
can  only  be  touched  on  in  passing  here,  and  it  is  touched 
on  merely  to  facilitate  our  exposition  of  the  compli- 
cated conditions  of  neural  discharge.  These  may  be  for- 
mulated in 

184.    Law  IV.    The  simultaneous  influence  of  several 
stimuli,  each  of  which  separately  excites  the  same 
centre,  is  cumulative :    stimuli  then  assist   each 
other,  and  their  resultant  is  their  arithmetical  sum. 
Simultaneous  stimuli,  each  of  which  excites  a  differ- 
ent centre,  interfere  with  each  other's  energy,  and 
their  resultant  is  their  algebraical  sum. 
In  this  law  there  is  a  condensed  expression  of  that  com- 
position of  forces  which  may  either  result  in  Discliarge  or 


330  THE   PHYSICAL  BASIS   OF   MIND. 

Arrest.  By  simultaneity  is  not  to  be  understood  merely 
the  coincidence  of  impressions,  but  also  the  reverberations 
of  impressions  not  yet  neutralized  by  others.  Thus  when 
Sensibility  is  tested  by  the  now  common  method,*  it  is 
found  that  if  one  leg  is  withdrawn  after  a  lapse  of,  say, 
ten  pendulum  beats,  the  other  leg,  which  has  not  been 
irritated,  will  nevertheless,  on  irritation,  be  withdrawn  in 
less  than  ten  beats,  provided  the  central  agitation  caused 
by  the  first  stimulation  has  not  yd  subsided.  But,  on  the 
contrary,  the  witlidrawal  \\ill  be  considerably  deferred,  or 
even  prevented  altogether,  if  at  the  same  time  that  the  leg- 
is  acted  on  by  the  acid,  a  more  powerful  excitation  takes 
place  in  some  other  part  of  the  body.  In  the  one  experi- 
ment we  see  simultaneous  excitation  in  the  same  centre 
and  the  same  direction.  In  the  other  simultaneous  exci- 
tation in  different  centres.  The  more  powerful  excitation 
suppresses  the  discharge  from  the  less  powerful ;  but 
although  it  prevails,  it  loses  just  as  much  force  as  it 
arrests.f 

185.  There  is  another  very  interesting  experiment  by 
Freusberg,  which  must  be  cited  here.|  When  the  sciatic 
nerve  is  divided,  tlie  frog's  leg  is  of  course  not  withdrawn 
from  the  acidulated  water,  because  in  that  case  no  sensory 
excitation  is  propagated  from  the  skin  to  the  centre ;  but 
although  there  is  no  stimulation  from  the  skin,  there  is 
one  from  the  muscles,  as  appears  in  the  fact  that  if  a  small 

*  A  frog's  brain  is  removed,  and  the  body  then  suspended  by  tlie  lower 
jaw,  the  legs  are  allowed  to  dip  into  a  slightly  acidulated  lii^uid,  the 
chemical  action  of  which  stimulates  the  skin. 

+  I  saw  a  patient  in  the  Berlin  Charite  whose  face  and  left  hand  were 
in  a  constant  .state  of  convulsive  twitching,  but  no  sooner  was  a  scar  on 
the  left  hand  (where  the  nerve  had  been  divided)  firmly  pressed  than  the 
twitch ings  ceased,  and  j^in  was  felt ;  on  removal  of  the  pressure,  pain 
ceased  and  the  twitchings  returned. 

t  Pfiuger's  Archiv,  1875.  No  one  interested  in  the  Reflex  Theory 
should  omit  a  careful  study  of  the  papers  by  FREUSBEno  and  Goltz.  I 
have  drawn  freely  from  them. 


THE  NERVOUS  MECHANISM.  331 

weight  be  suspended  on  this  leg,  the  other  leg  is  more 
rapidly  withdrawn  from  the  acidulated  water  —  the  action 
of  the  muscles  having  affected  the  centre  and  increased 
its  excitability. 

186.  When  the  motor  group  of  one  leg  is  moderately 
stimulated,  the  discharge  is  confined  to  the  muscles  of  that 
one  leg ;  and  according  to  Herzen  the  excitability  of  the 
motor  group  of  the  other  leg  is  thereby  somewhat  dimin- 
ished. But  if  the  stimulation  be  increased,  there  is  an 
irradiation  to  the  other  group,  which  irradiation,  although 
not  sufficient  to  excite  a  discharge,  renders  it  much  more 
ready  to  discharge,  so  that  a  feeble  stimulus  suffices.  This 
accords  with  Setschenow's  observations,  and  is  confirmed 
by  Freusberg's  experiment,  in  which,  when  one  leg  was 
stimulated  by  acid,  if  the  acid  were  not  wiped  off  but 
allowed  to  keep  up  the  irritation,  the  other  leg  moved 
without  being  irritated ;  and  this  other  leg  having  come 
to  rest,  when  in  its  turn  dipped  in  the  acid,  was  more  rap- 
idly withdrawn  than  the  first  leg  had  been  on  first  being 
stimulated ;  showing  that  the  central  groups  liad  become 
more  excitable  by  the  stimulation  of  either  leg. 

187.  While  it  is  intelligible  that  an  excitation  of  one 
group  should  increase  tlie  activity  of  neighboring  groups, 
by  an  increase  of  the  vascular  activity  of  the  region,  it  is 
not  so  readily  intelligible  why  the  feebler  excitation  of 
one  group  should  diminish  the  excitability  of  its  neighbor ; 
yet  the  facts  seem  to  warrant  both  statements. 

188.  The  conditions  which  determine  Discharge  are 
obscure.  We  may,  however,  say  that  anatomical  and 
physiological  data  force  the  conclusion  that  whenever  the 
central  tissue  is  powerfully  stimulated  in  any  one  part, 
there  is  either  a  discharge,  or  a  greater  tension  (tendency 
to  discharge)  in  every  other  part ;  in  consequence  of  which, 
every  fresh  stimulus  in  the  same  direction  finds  the  parts 
more  prepared  to  react;  while  every  fresli  stimulus  in  a 


332  THE  niYsiCAL  basis  of  mind. 

contran/  direction  meets  with  a  proportional  resistance. 
Stated  thus  generally,  the  principle  is  clear  enough ;  but 
the  immense  complication  of  stimulations,  and  the  statical 
variableness  of  the  organs,  renders  its  ap})lication  to  par- 
ticular cases  extremely  obscure.  Why  does  the  ticking 
of  a  clock  arrest  the  attention,  even  with  unpleasant  ob- 
trusiveness,  at  one  time,  and  presently  afterwards  cease  to 
be  heard  at  all  ?  Why  does  the  cut  of  a  knife  cause  in- 
tense pain,  and  a  far  greater  cut  received  during  the  heat 
and  agitation  of  a  quarrel  pass  unfelt  ?  Why  will  the 
same  external  force  excite  convulsions  in  all  the  muscles, 
and  at  another  time  scarcely  be  distinguishable  ?  These 
are  consequences  of  the  temporary  condition  of  the  cen- 
tres ;  but  tliere  are  permanent  conditions  which  in  some 
organisms  determine  equally  variable  results.  Thus  the 
shock  of  terror  which  will  simply  agitate  one  person,  will 
develop  an  epileptic  attack  in  another,  and  insanity  in  a 
third ;  just  as  exposure  to  cold  will  in  one  person  congest 
the  liver,  in  another  the  lungs.  A  loud  and  sudden  sound 
causes  winking  in  most  persons,  and  in  many  a  sort  of 
convulsive  shock.  The  harsh  noise  of  a  file  causes  a 
shiver  in  some  persons,  and  in  others  "sets  the  teeth  on 
edge,"  while  in  others  it  causes  an  increased  flow  of  saliva. 
189.  Nerves  and  centres  liave  different  degrees  of  ex- 
citability. The  nerve-terminals  in  the  skin  are  more 
sensitive  to  impressions  than  those  in  the  mucous  mem- 
brane ;  those  in  the  alimentary  canal  are  more  sensitive 
than  those  in  the  peritoneum  ;  and  all  nerve-terminals  are 
more  sensitive  tlian  nerve-trunks.  A  touch  on  the  sur- 
face of  the  larynx  will  produce  a  cough,  but  the  nerve- 
trunk  itself  may  l)e  pinched  or  galvanized  without  pro- 
ducing any  such  reflex.  Moreover,  there  is  tlie  difference 
of  grouping.  If  the  skin  of  the  abdomen  be  tickled,  there 
is  a  reflex  on  the  adductor  and  extensor  muscles  of  the 
leg ;  but  these  movements  are  reversed  if  the  skin  of  the 


THE  NERVOUS  MECHANISM.  333 

back  be  tickled.  Xor  indeed  are  these  movements  invari- 
able in  either  case ;  the  one  series  will  sometimes  quite 
suddenly  change  to  the  other,  if  the  irritation  is  kept  up. 
That  one  and  the  same  stimulus  applied  to  the  same  spot 
should  now  excite  this  group  and  now  the  other,  shows 
that  both  motor  groups  are  ahected,  and  that  the  discharge 
takes  place  from  the  one  which  at  the  time  being  is  in  the 
highest  tension.  The  alternation  of  tension  explains  rhyth- 
mical discharge. 

THE   LAW   OF  ARREST. 

190.  The  Law  of  Arrest  is  only  another  aspect  of  the 
Law  of  Discharge,  and  may  be  regarded  as  the  conflict  of 
excitations.  If  a  stranger  enters  the  room  where  a  woman 
lies  in  labor,  there  will  often  be  caused  a  sudden  cessation 
of  the  uterine  contractions.*  Again,  every  one  knows  how 
the  breathing  and  the  beating  of  the  heart  are  arrested 
by  the  idea  of  danger.  The  arrest  is  in  each  of  the  three 
cases  only  temporary,  because  when  the  shock  of  the  nev/ 
stimulus  has  caused  its  discharge  (arrest),  the  peripheral 
irritation  which  caused  the  former  discharges  resumes  its 
influence,  and  uterus,  heart,  and  diaphragm  begin  to  move 
again,  even  more  energetically.  Note,  moreover,  that  not 
only  will  the  cerebral  excitation  arrest  the  spinal  dis- 
charge—  an  idea  check  the  contractions  of  the  uterus  or 
the  heart  —  but  the  reverse  also  takes  place.  The  brain 
of  the  woman  may  be  intently  occupied  with  some  scheme 
for  the  education  or  welfare  of  her  expected  child,  but  no 
sooner  do  the  labor  pains  set  in,  than  all  these  cerebral 
combinations  are  arrested. 

191.  One  sensation  arrests  another  ;  one  idea  displaces 

*  Sir  Jameh  Paget  hag  an  interesting  collection  of  facts  which  illus- 
trate tliis  I>aw  of  Arrest,  in  his  paper  on  "  Stamnicrinfj  with  other  Organs 
than  those  of  Speech,"  IJn'tish  Medical  Journal,  1808,  Vol.  II.  p.  437, 
reprinted  in  his  Clinical  Lectures  and  Essaya,  1875,  p.  77. 


334  THE   niYSIGAL  BASIS   OF   MIND. 

another.  If  the  foreleg  of  a  headless  frog  be  irritated, 
the  hind-leg  will  also  be  moved  by  the  stimulation ;  or 
vice  versa.  Here  there  has  been  a  propagation  of  the  ex- 
citation in  either  direction.  But  if  while  the  legs  are 
thus  irritated,  and  the  centres  are  ready  to  discharge,  an- 
other and  more  powerful  irritation  reach  the  centre  — 
say  by  pinching  the  skin  of  the  back  —  there  will  be  no 
discharge  on  the  legs.  If  the  vagus  be  irritated,  tlie  heart 
is  arrested ;  but  this  does  not  take  place  if  at  the  same 
time,  or  immediately  before,  the  foot  has  been  sharply 
pinched.  A  few  gentle  taps  on  the  abdomen  suffice  to 
stop  the  heart ;  but  if  a  drop  of  acid  be  previously  placed 
on  the  skin,  we  tap  in  vain,  the  heart  continues  to  beat. 
Brown  Sequard  cites  several  cases  in  which  convulsions 
were  arrested  by  irritation  of  sensitive  surfaces ;  *  and 
Dr.  Crichton  Browne  records  a  case  of  a  patient  in  whom 
there  was  abolition  of  spinal  reflex,  due  to  cerebral  irrita- 
tion :  tickling  the  soles  of  the  feet,  or  pricking  the  toes, 
which  normally  excites  reflex  movements,  in  this  case 
excited  none  whatever.  "  This  seems  to  prove  that  nerv^e 
currents,  set  in  motion  by  irritation  of  the  brain,  or  some 
of  its  convolutions,  transmitted  down  the  cord,  may  in- 
hibit reflex  action."!  Examples  might  indefinitely  be 
multiplied.  Pinch  the  skin  of  a  rabbit  between  the  eyes, 
and  you  will  observe  that  pulse  and  respiration  are  slack- 
ened ;  but  if  the  tail,  which  is  very  sensitive,  be  pinched, 
this  slackening  is  only  momentary,  and  is  succeeded  by  a 
quickening  —  unless  the  pain  be  great.  Even  the  effect 
of  intense  pain  may  be  neutralized  by  stimulating  the 
vagus  —  just  as  the  effect  of  stimulating  the  vagus 
may  be  neutralized  by  pain.  Claude  Bernard  found 
that  having  dropped  ammonia  on  the  eyelid  of  a  dog, 
the  pain  caused  a  convulsive  closure  of  the  lid ;   but 

*  Archwes  de  Physiol.,  1868,  p.  157. 

t   TVcst  Riding  Lunatic  Asylum  Reports,  1874,  p.  200. 


THE  NERVOUS  MECHANISM.  335 

on  galvanizing  the  vagus,  the  lid  opened  again,  to  be 
closed  when  the  galvanism  ceased*  When  the  heart  is 
beating  faintly  (as  in  syncope),  any  irritating  vapor  ap- 
plied to  the  nostrils  will  cause  a  more  energetic  pulsa- 
tion ;  yet  a  very  irritating  vapor  lowers  the  action  of  the 
heart  beating  normally,  and  will  even  arrest  that  of  a 
rabbit.  Over-stimulation  has  almost  always  the  opposite 
effect  of  moderate  stimulation. 

192.  "While  there  seems  every  reason  to  believe  that 
an  excitation  necessarily  affects  the  whole  cerebro-spinal 
axis,  there  is  no  doubt  that  there  is  a  certain  restriction 
of  this  irradiation  to  definite  paths,  i.  e.  the  responsive 
discharge  is  confined  to  definite  groups.  Some  of  tliese 
restrictions  are  connate  pathways :  we  bring  tliem  witli 
us  at  birtli ;  but  most  of  them  8,re  pathways  acquired 
after  birth.  The  boy  who  sheds  tears  at  parting  from  his 
mother  when  he  goes  to  school,  will  shed  no  tears  when 
he  parts  from  her  to  go  to  college,  nay,  perhaps  will  shed 
none  when  he  parts  from  her  forever :  not  that  his  love 
has  lessened,  but  that  the  idea  of  such  expression  of  it  as 
"unmanly"  has  become  an  organized  tendency  and  arrests 
the  tears.  A  youth  of  southern  race,  who  has  not  learned 
to  be  ashamed  of  tears,  weeps  freely  under  such  circum- 
stances. 

193.  The  pathways  organized  at  birth  are  not  many. 
Examples  are  the  inspiration  which  follows  expiration ; 
the  movements  of  coughing  when  the  larynx  is  tickled ; 
the  movements  of  swallowing,  sneezing,  etc.  Even  these 
may  be  arrested  for  a  brief  time  by  what  is  called  "the 
will";  but  when  once  the  discharge  begins  in  any  part 
of  the  mechanism,  the  whole  group  is  necessarily  involved 
and  the  action  is  then  inevitable.  Many  of  the  reflex 
actions  which  are  universal  are  nevertlieless  acquired. 
"Winking,  for  instance,  when  an  object  approaches  the 

*  Claude  Bernakd,  Syslivic  Ncrvcux,  I.  383. 


33 G  THE   PHYSICAL  BASIS   OF  MIND. 

eye,  is  universal  among  us,  but  is  never  seen  in  infants, 
nor  in  animals.  It  is  even  doubtful  whether  the  draw- 
ing up  of  the  leg  when  the  toes  are  pinched  is  not  an 
acquired  reflex.  Doubtful,  I  mean,  in  this  sense,  that 
although  the  fact  of  non-withdrawal  is  observable  in 
infants,  who  cannot  localize  their  sensations,  tliis  may  be 
due  to  the  imperfect  development  of  their  nervous  sys- 
tem. Mr.  Spalding  has  proved  that  although  the  callow 
bird  cannot  fly,  the  mechanism  of  flight  is  no  sooner 
developed  than  the  action  follows  at  once,  without  any 
previous  tentative  experiences. 

194.  By  experience  we  learn  to  restrict  the  paths  of 
irradiation,  so  as  to  wink  witli  one  eye  while  the  other  is 
unmoved,  to  bend  one  finger  wdiile  the  rest  are  extended, 
to  move  one  limb,  or*  one  group  of  muscles,  while  the 
others  are  at  rest ;  in  short,  to  execute  any  one  particular 
action,  and  not  at  the  same  time  agitate  superfluously 
many  other  organs.  The  boy  when  first  learning  to  write 
is  unable  to  prevent  the  simultaneous  motions  of  tongue 
and  legs,  which  are  ludicrously  irrelevant  to  the  purpose 
of  writing ;  but  he  learns  to  keep  all  his  organs  in  sub- 
jection, and  only  the  eyes  and  hands  active.*  An  anal- 
ogous restriction  takes  place  in  thinking.  A  train  of 
thought  is  kept  up  by  the  exclusion  of  all  suggestions 
which  are  not  pertinent ;  and  the  power  of  the  thinker  is 
precisely  this  power  of  concentration. 

THE   HYPOTHESIS   OF   INHIBITORY   CENTRES. 

195.  The  facts  and  their  formulated  laws  which  have 
just.been  adduced  furnish  a  sufficient  explanation  of  all  the 
phenomena  of  arrest  which  of  late  years  have  been  detached 

*  See  the  excellent  remarks  of  Dr.  Lauder  Bruxton  on  this  point  in 
his  paper  on  Inhibition  in  the  West  Riding  Lunatic  Asylum  Reports, 
1874,  p.  180. 


THE  NERVOUS  MECHANISM.  337 

and  assigned  to  a  special  mechanism  of  inliibitory  nerves 
and  centres.  In  spite  of  the  eminent  authorities  counte- 
nancing the  hypothesis  of  a  particuhir  set  of  inhibitory 
nerves,  and  particular  centres  of  inhibition,  I  must  con- 
fess that  the  hypothesis  appears  to  me  inadmissible ;  and 
that  I  side  with  those  physiologists  who  hold  that  each 
nerve  and  each  centre  has  its  inhibitory  action.  Indeed, 
if  the  action  of  arrest  be,  as  I  maintain,  only  another 
aspect  of  the  action  of  discharge,  the  result  of  the  conflict 
of  forces,  to  say  that  all  centres  have  the  property  of  ex- 
citation, is  to  say  that  all  have  the  properties  of  discharge 
and  arrest :  the  discharge  is  only  the  resultant  of  the  con- 
flict along  the  line  of  least  resistance ;  the  arrest  is  the 
c'ffect  of  the  conflict  along  the  line  of  greatest  resistance. 
The  observed  phenomena  of  arrest  are  so  varied  and  nu- 
merous that  the  npliolders  of  the  inhibitory  hypothesis 
have  been  forced  to  invent  not  only  arresting  centres,  but 
centres  which  arrest  these  arresting  centres !  Dr.  Lauder 
Brunton  candidly  remarks  :  "  At  present  our  notions 
of  nervous  action  seem  to  be  getting  as  involved  as  the 
Ptolemaic  system  of  astronomy,  and  just  as  ei)icyelos 
became  heaped  upon  cycles,  so  nerve-centres  arc  being 
added  to  nerve-centres.  And  yet,  clumsy  though  the  sys- 
tem may  be,  it  serves  at  present  a  useful  purpose,  and 
may  give  real  aid  until  a  better  is  discovered."  I  do  not 
think  a  Copernicus  is  needed  to  discover  a  better.  The 
Law  of  Arrest  as  a  general  neural  law  suffices,  wlien  the 
right  conception  of  a  wntrc  as  a  i)hysiological  rather  than 
an  anatomical  designation  is  admitted.     (See  p.  173.) 

19G.  It  would  be  out  of  place  liere  to  consider  the  con- 
flicting evidence  wliich  at  present  renders  the  question 
of  the  movements  of  the  heart  one  of  the  most  unsatis- 
factory in  the  whole  range  of  experimental  jiliysiology. 
After  devoting  much  time  to  it,  and  after  writing  a  long 
chapter  on  it,  I  suppress  wliat  I  had  written,  and  content 

VOL.   III.  15  V 


338  THE  PHYSICAL  BASIS   OF  MIND. 

myself  with  tlie  statement  that  no  advantage  whatever  is 
derived  from  the  hypothesis  of  a  special  mechanism  of 
arrest,  unless  perhaps  in  giving  a  temporary  precision  to 
the  direction  of  research.  I  mean  that  the  search  for 
special  centres  may  lead  to  the  discovery  of  the  partic- 
ular paths  to  which  an  impulse  is  restricted  in  any  one 
action :  as,  for  instance,  the  vagus  in  retarding  the  pulsa- 
tion of  the  heart.  If  the  cerebrum  can  determine  a  move- 
ment, and  combine  various  movements,  it  is  a  centre  of 
arrest ;  if  the  cerebellum  can  determine  and  regulate 
movements,  it  is  a  centre  of  arrest ;  if  the  medulla  oblon- 
gata can  determine  and  regulate  movements,  it  is  a  centre 
of  arrest ;  if  the  medulla  spinalis  can  determine  and  com- 
bine movements,  it  is  a  centre  of  arrest ;  if  a  nerve  can 
dilate  a  constricted  blood-vessel,  or  constrict  a  dilated 
one,  it  is  a  nerve  of  arrest.  In  other  words,  every  centre 
exerts  its  action  either  in  discharging,  or  in  arresting  the 
discharge  of  some  other  centre. 

The  physiological  process  of  Arrest  may  be  physically 
interpreted  as  Interference  ;*  not  that  the  process  in 
nerve-tissue  is  to  be  understood  as  the  same  as  that  ob- 
served in  fluids,  or  that  the  metaphor  of  neural  waves  is 
to  be  taken  for  more  than  an  intelligible  picturing  of  the 
process ;  the  difference  in  the  two  agents  forbids  our 
admitting  the  resemblance  to  be  more  than  analogical. 
Thus  interpreted,  however,  we  see  that  not  only  will  one 
centre  arrest  the  action  of  another,  but  one  nerve  may  be 
made  to  arrest  itself!  I  mean  that,  under  similar  condi- 
tions of  interference,  the  stimulation  which  normally  fol- 
lows on  external  stimulus  may  be  inhibited  by  a  previous, 
or  a  counter  stimulation.     Thus  the  nerve  which  will  be 

*  The  interesting  question  of  interference  lias  been  experimentally 
treated  by  "VYundt  in  his  recently  published  Meclianik  der  Kerven,  1876, 
and  theoretically  as  wave-movement  by  Medem,  Grundziige  ciner  exakten 
Psychologic,  1876. 


THE  NERVOUS  MECHANISM.  339 

stimulated  by  a  chemical  or  mechanical  stimulus,  wholly 
fails  to  react  if  a  constant  current  is  passing  through  it, 
although  this  constant  current  does  not  itself  cause  a  con- 
stant contraction.  Eemove  the  electrodes,  and  then  the 
chemical  or  mechanical  stimulus  takes  effect.  Or  the 
experiment  may  be  reversed :  let  the  nerve  be  placed  in  a 
saline  solution,  and  the  muscles  will  be  at  once  thrown 
into  violent  contraction  ;  if  the  electrodes  are  now  applied 
to  the  nerve,  the  contractions  suddenly  cease,  to  begin 
again  directly  the  electrodes  are  removed. 

ANATOMICAL  INTERPRETATION  OF  THE  LAWS. 

197.  The  problem  for  the  anatomist  is  twofold :  First, 
given  the  organ,  he  has  to  determine  its  function,  or  vice 
versa,  given  the  part  of  an  organ,  to  determine  its  func- 
tional relation ;  secondly,  given  the  function,  he  has  to 
determine  its  organ.  The  structural  and  functional  rela- 
tions of  nerves  and  centres  have  been  ascertained  in  a 
general  way ;  we  are  quite  sure  that  the  posterior  nerves 
carry  excitations  from  sensitive  surfaces,  that  the  anterior 
nerves  carry  excitations  to  muscles  and  glands ;  and  that 
the  central  gray  substance  not  only  reflects  a  sensory  exci- 
tation as  a  motor  excitation,  but  propagates  an  excitation 
along  the  whole  cerebro-spinal  axis.  But  when  we  come 
to  a  more  minute  analysis  of  the  functional  activities,  and 
endeavor  to  assign  their  respective  values  to  each  part  of 
the  organic  mechanism,  the  excessiv'e  complexity  and  deli- 
cacy of  the  mechanism  baffles  research.  We  are  forced 
to  grope  our  way  ;  and  the  light  of  tlie  hypothetic  lamps 
whicli  we  hold  aloft  as  often  misdirects  as  helps  us.  The 
imaginary  anatomy  which  at  present  gains  acceptance,  no 
doubt  seems  to  simplify  explanations ;  but  this  seeming 
turns  out  to  be  illusory  when  closely  examined.  The 
imagined  arrangement  of  fibres  and  cells  we  have  seen  to 


340  THE   PHYSICAL   BASIS   OF   MIND. 

be  not  in  agreement  with  observation  ;  and  were  it  demon- 
strable, it  would  not  account  for  the  laws  of  propagation. 
Suppose  sensory  fibres  to  terminate  in  cells,  and  fibres 
from  these  to  pass  upivards  to  other  sensory  cells  and 
transversely  to  motor  cells,  how  in  such  a  connected  sys- 
tem could  irradiations  take  jjlace,  if  the  law  of  isolated 
conduction  were  true  ?  And  how  could  isolated  conduc- 
tion take  place,  if  the  excitation  of  a  part  were  necessa- 
rily the  excitation  of  the  whole?  Why,  for 'example,  is 
pain  not  always  irradiated  ?  Why  is  it  even  localized  in 
particular  spots,  determining  movements  in  particular 
muscles  ;  and  when  irradiation  takes  place,  why  is  it  cir- 
cumscribed, or  —  and  this  is  very  noteworthy  —  mani- 
fested in  two  widely  difierent  places,  the  intercostal  and 
trigeminal  nerves  ?  Why  does  the  irritation  of  intestinal 
worms  manifest  itself  now  by  troubles  of  vision,  now  by 
noises  in  the  ear,  and  now  by  convulsions  ? 

198.  Answers  to  such  questions  must  be  sought  else- 
where. Our  first  search  should  be  directed  to  the  ana- 
tomical data,  which  have  hitherto  been  so  imprudently 
disregarded.  Under  the  guidance  of  the  laws  formulated 
in  this  chapter,  let  us  accept  the  anatomical  fact  of  a  vast 
network  forming  the  ground-substance  in  which  cells  and 
fibres  are  embedded,  and  with  which  they  are  continuous  ; 
let  us  accept  the  physiological  principle  of  similarity  of 
property  with  similarity  of  composition  and  structure ; 
let  us  accept  the  hypothesis  that  the  discharge  of  neural 
energy  is  dependent  on  the  degree  of  stimulus  and  the 
degree  of  tension  at  the  time  being  —  and  we  shall  have 
at  least  a  general  theory  of  the  process,  though  there  will 
still  remain  great  obscurities  in  particular  applications. 
We  shall  have  before  us  a  vast  network  of  pathways,  all 
equally  capable  of  conducting  an  excitation,  but  not  all 
equally  and  at  all  moments  open.  It  will  always  be  diffi- 
cult to  determine  what  are  the  conditions  which  at  any 


THE  NERVOUS  MECHANISM.  341 

nioment  favor  or  obstruct  particular  openings.  Paths  that 
have  been  frequently  traversed  will  of  course  be  more 
readily  traversed  again ;  but  this  very  facility  will  some- 
times be  an  obstacle,  since  it  will  have  caused  that  path 
to  be  preoccupied,  or  have  fatigued  the  organ  to  which  it 
leads. 

199.  Since  the  escape  of  an  excitation  must  always  be 
along  the  lines  of  least  resistance,  an  obvious  explanation 
of  the  restriction  to  certain  paths  has  been  to  assume  that 
some  fibres  and  cells  have  naturally  greater  resistance 
than  others.  But  this  explanation  is  simply  a  restate- 
ment of  the  fact  in  other  words.  What  is  this  greater 
resistance  ?  Why  is  it  present  in  one  fibre  rather  than  in 
another  ?  We  should  first  have  to  settle  whether  the 
resistance  was  in  the  nervous  pathway  itself,  or  in  the 
centre,  or  in  the  organ  innervated ;  an  excitation  might 
pass  along  the  nervous  tract,  yet  fail  to  change  the  state 
of  the  centre,  or  the  organ,  sufficiently  to  produce  an  ap- 
preciable response ;  and  only  those  parts  where  an  appre- 
ciable response  was  produced  would  then  be  considered  as 
having  had  the  pathways  of  propagation  open. 

200.  When  we  reflect  on  the  innumerable  stimulations 
to  which  the  organism  is  subjected  from  so  many  various 
l)oints,  and  remember  further  that  each  stimulation  leaves 
behind  it  a  tremor  ivhieh  does  not  immediately  subside,  we 
shall  conceive  something  of  the  excessive  complexity  of 
the  mechanism,  and  marvel  how  any  order  is  established 
in  the  chaos.  What  we  must  firmly  establish  in  our 
minds  is  tliat  the  mechanism  is  essentially  a  Jluctuating 
one,  its  elements  being  combined,  recombiued,  and  re- 
.solved  under  infinite  variations  of  stimulation.  If  it  were 
a  mechanism  of  fixed  relations,  sucli  as  we  find  In  ma- 
chines, or  in  the  "  mechanism  of  the  heavens,"  we  might 
accept  the  notion  of  certain  organites  having  greater  resist- 
ance as  a  consequence  of  their  structure,  just  as  one  mus- 


342  THE  niYsicAL  basis  of  mind. 

cle  resists  being  moved  by  the  impulse  which  will  move 
another.  Nor  is  it  doubtful  tliat  such  differences  exist  in 
nervous  organites ;  but  tlie  laws  of  central  excitation  are 
not  interpretable  by  any  such  hypothesis,  since  we  know 
that  tlie  paths  which  were  closed  against  an  impulse  of 
considerable  energy  may  be  all  open  to  an  impulse  of 
feebler  energy,  and  that  a  slight  variation  in  the  stimulus 
will  be  followed  by  a  wide  irradiation.  For  example,  a 
grain  or  two  of  snuff'  will  excite  the  violent  and  complex 
act  of  sneezing,  but  the  nerves  of  the  nasal  cavity  may 
be  pinched,  cut,  or  rubbed,  without  producing  any  such 
result.  One  group  of  nervous  organites  will  fail  to  in- 
volve tlie  activity  of  neighboring  groups ;  and  the  simple 
movement  of  a  single  organ  is  then  all  that  appreciably 
follows  the  stimulation ;  yet  by  a  slight  change  in  the 
stimulation,  the  organites  are  somewhat  differently 
grouped,  and  the  result  is  a  complex  movement  of  many 
organs.  It  is  this  fluctuation  of  combination  in  the  organ- 
ites which  renders  education  and  progress  possible.  Those 
combinations  which  have  very  frequently  been  repeated 
acquire  at  last  an  automatic  certainty. 

"We  are  now  in  a  position  to  examine  with  more  precis- 
ion the  extremely  important  laws  of  nervous  action  which 
are  involved  in  the  phenomena  designated  by  the  terms 
Eeflex  Action,  Automatic  Action,  and  Voluntary  Action. 


PROBLEM    III. 


ANIMAL  AUTOMATISM. 


"  L'organisme  le  plus  complexe  est  vrn  vaste  mecanisme  qui  resulte  de  I'as- 
semblage  de  mecanismes  secondaires."  —  Claude  Bernard. 

' '  Les  corps  vivants  sont  machines  a  rinfini."  —  Leibnitz. 

"  Noi  lamentiamo  con  Majendie  clie  nel  linguaggio  fisiologico  siensi  intruse 
le  preopinioni  psicologiche  col  trascico  inevitabile  del  vocaboli,  ai  quali  co- 
deste  preopinioni  si  trovano  legate.  Probabilmente  questa  fu  una  delle  princi- 
pal! cagioni  degli  errori  e  degli  equivoci  anatomofisiologici,  da  cui  non  poterono 
svincolarsi,  a  loro  insaputa,  1  cultori  sperimentali  della  scienza,  perche  nell' 
interpretare  i  fenomeni  osservati  erano  obbligati  ad  usare  il  linguaggio  di  una 
falsa  moneta  in  corso."  —  Lussana  e  Lemoigne,  Fisiologia  dei  Centri  Ner- 
vosi,  1871, 1.  16. 


ANIMAL   AUTOMATISM. 


CHAPTEE    I. 

THE  COUKSE  OF  MODEEN  THOUGHT. 

1,  MoDEKN  Philosophy  has  moved  along  two  increas- 
ingly divergent  lines.  One,  traversed  by  Galileo,  Des- 
cartes, Newton,  and  Laplace,  had  for  its  goal  the  absolute 
disengagement  of  the  physical  from  the  mental,  i.  e.  the 
objective  from  the  subjective  aspect  of  phenomena,  so 
that  the  physical  universe,  thus  freed  from  all  the  com- 
plexities of  Feeling,  might  be  interpreted  in  mechanical 
terms.  As  a  preliminary  simplification  of  the  problem 
tliis  was  indispensable  ;  only  by  it  could  the  First  Notion 
of  primitive  speculation  be  replaced  by  the  Theoretic 
Conception  of  scientific  speculation.*  The  early  thinker 
inevitably  invested  all  external  objects  with  properties 
and  qualities  similar  to  those  he  assigned  to  human 
beings,  and  their  actions  he  assigned  to  human  motives. 
Sun,  moon,  and  stars  seemed  living  beings;  flames,  streams, 
and  winds  were  supposed  to  be  moved  by  feelings  sucli 
as  those  known  to  move  animals  and  men.  Nor  was 
any  other  conception  then  possible :  men  could  only  in- 
terpret the  unknown  by  the  known,  and  their  standard 
of  all  action  was  necessarily  drawn  from  their  own  ac- 
tions.    Not  having  analyzed  Volition  and  Emotion,  above 

*  On  the  distinction  between  first  notions  and  theoretic  conceptions, 
see  Problems  of  Life  and  Mind,  Vol.  II.  p.  277. 
10* 


346  THE   niYSICAL   BASIS   OF   MIND. 

all  not  having  localized  these  in  a  nenro-muscular  system, 
men  could  not  suspect  that  the  movements  of  planets 
and  plants,  and  of  streams  and  stones,  had  motors  of  a 
different  kind  from  the  movements  of  animals.  The  sci- 
entific conception  of  inert  insensible  JNIatter  was  only 
attained  through  a  long  education  in  abstraction ;  and  is 
assuredly  never  attained  by  animals,  or  by  savages.  But 
no  sooner  were  vital  conditions  recognized,  than  the  dif- 
ference between  vital  and  mechanical  movements  emerged. 
When  men  learned  that  many  of  their  own  actions  were 
unaccompanied  either  by  Love  or  Hate,  by  Pleasure  or 
Pain,  and  that  many  were  unprompted  by  conscious  in- 
tention, while  others  were  unaccompanied  by  conscious 
sensation,  they  easily  concluded  that  wherever  the  special 
conditions  of  Feeling  were  absent,  the  actions  must  have 
some  other  motors.  Intelligence,  Emotion,  Volition,  and 
Sensation  being  one  by  one  stripped  away  from  all  but  a 
particular  class  of  bodies,  nothing  remained  for  the  other 
bodies  but  insensible  Matter  and  Motion.  This  was  the 
Theoretic  Conception  which  science  substituted  for  the 
First  Notion.  It  was  aided  by  the  observation  of  the 
misleading  tendency  of  interpreting  physical  phenomena 
by  the  human  standard,  substituting  our  fancies  in  the 
place  of  facts,  manipulating  the  order  of  the  universe  ac- 
cording to  our  imagination  of  what  it  might  be,  or  ought 
to  be.  Hence  the  vigilance  of  the  new  school  in  sup- 
pressing everything  pertaining  to  the  subjective  aspect 
of  phenomena,  and  the  insistance  on  a  purely  objective 
classification,  so  that  by  this  means  we  might  attain  to 
a  knowledge  of  things  as  they  are.  By  thus  withdraw- 
ing Life  and  Mind  from  Nature,  and  regarding  tlie  uni- 
verse solely  in  the  light  of  Motion  and  the  laws  of  Motion, 
two  great  scientific  ends  were  furthered,  namely,  a  clas- 
sification of  conceptions,  and  a  precision  of  terms.  Ob- 
jective phenomena  made  a  class  apart,  and  the   great 


ANIMAL  AUTOMATISM.  '  347 

aim  of  research  was  to  find  a  mathematical  expression 
for  all  varieties  under  this  class.  Masses  were  conceived 
as  aggregates  of  Atoms,  and  these  were  reduced  to  mathe- 
matical points.  Forces  were  only  different  modes  of  Mo- 
tion. All  the  numberless  difierences  which  perception 
recognized  as  qualities  in  things,  were  reduced  to  mere 
variations  in  quantity.  Thus  all  that  was  particular  and 
concrete  became  resolved  by  analysis  into  what  was  gen- 
eral and  abstract.  The  Cosmos  then  only  presented  a 
problem  of  Mechanics. 

2.  During  this  evolution,  the  old  DuaUsm  (which  con- 
ceived a  material  universe  sharply  demarcated  from  the 
mental  universe)  kept  its  ground,  and  attained  even 
greater  precision.  The  logical  distinction  between  Matter 
and  Mind  was  accepted  as  an  essential  distinction,  i.  e. 
representing  distinct  reals.  Tliere  was  on  the  one  side  a 
group  of  phenomena,  Matter  and  Force  ;  on  the  other  side 
an  unallied  group,  Feeling  and  Thought :  between  them 
an  impassable  gulf.  How  the  two  were  brought  into 
relation,  each  acting  and  reacting  on  the  other,  was 
(Usmissed  as  an  "  insoluble  mystery  "  —  or  relegated  to 
Metaphysics  for  such  minds  as  chose  to  puzzle  over  ques- 
tions not  amenable  to  experiment.  Physics,  confident 
in  the  possession  of  mathematical  and  experimental 
methods  which  yielded  definite  answers  to  properly  re- 
stricted questions,  peremptorily  refused  to  listen  to  any 
suggestion  of  the  kind.  And  the  career  of  Physics  was 
so  triumphant  that  success  seemed  to  justify  its  indif- 
I'erence. 

3.  In  our  own  day  this  analytical  school  has  begun  to 
extend  its  metliods  even  to  the  mental  group.  Having 
reduced  all  the  objective  group  to  mathematical  treat- 
ment, it  now  tries  to  bring  the  sul)jective  group  also 
witliin  its  range.  Not  only  has  there  been  more  than 
one  attempt   at  a  mathematical  Psychology  ;    but   also 


348  THE   PHYSICAL   BASIS   OF  MIND, 

attempts  to  reduce  Sensibility,  in  its  subjective  no  less 
than  in  its  objective  aspect,  to  molecular  movement. 
Here  also  the  facts  of  Quality  are  translated  into  facts 
of  Quantity ;  and  all  diversities  of  Feeling  are  inter- 
preted as  simply  quantitative  differences. 

4.  Tims  far  the  one  school.  But  while  this  Theoretic 
Conception  stripped  Nature  of  consciousness,  motive,  and 
passion,  rendering  it  a  mere  aggregate  of  mathematical 
relations,  a  critical  process  was  going  on,  which,  analyz- 
ing the  nature  of  Perception,  was  rapidly  moving  towards 
another  goal.  Locke,  Berkeley,  Hume,  and  Kant,  direct- 
ing their  analysis  exclusively  to  the  subjective  aspect  of 
phenomena,  soon  broke  down  the  barriers  between  the 
physical  and  mental,  and  gradually  merged  the  former  in 
the  latter.  Matter  and  its  qualities,  hitherto  accepted  as 
independent  realities,  existing  where  no  Mind  perceived 
them,  were  now  viewed  as  the  creations  of  Mind  — 
their  existence  was  limited  to  a  state  of  the  percipient. 
The  old  Dualism  was  replaced  by  Idealism.  The  Cosmos, 
instead  of  presenting  a  problem  of  Mechanics,  now  pre- 
sented a  problem  of  Psychology.  Beginning  with  what 
are  called  the  secondary  qualities  of  Matter,  the  psycho- 
logical analysis  resolved  these  into  modes  of  Feeling. 
"  The  heat  which  the  vulgar  imagine  to  be  in  the  fire  and 
the  color  they  imagine  in  the  rose  are  not  there  at  all, 
but  are  in  us — mere  states  of  our  organism."  Having 
gained  this  standing-place,  there  was  no  difficulty  in  ex- 
tending the  view  from  the  secondary  to  the  primary  qual- 
ities. These  also  w^ere  perceptions,  and  only  existed  in 
the  percipient.  Nothing  then  remained  of  Matter  save 
the  hypothetical  unknown  x  —  the  postulate  of  specu- 
lation. Kant  seemed  forever  to  have  closed  the  door 
against  the  real  Cosmos  when  he  transformed  it  into  a 
group  of  mental  forms  —  Time,  Space,  Causality,  Quan- 
tity, etc.     He  propounded  what  may  be  called  a  theory 


ANIMAL  AUTOMATISM.  349 

of  mental  Dioptrics  whereby  a  pictured  universe  became 
possible,  as  Experience  by  its  own  a  •priori  laws  moulded 
itself  into  a  consistent  group  of  appearances,  which  pro- 
duced tlie  illusion  of  being  a  group  of  realities.  He  ad- 
mitted, indeed,  that  by  the  operation  of  Causality  we  are 
compelled  to  believe  in  a  Real  underlying  the  appear- 
ances ;  but  the  very  fact  that  this  Causality  is  a  subjective 
law,  is  proof,  he  said,  of  its  not  being  an  objective  truth. 
Thus  the  aim  of  the  mechanical  conception  was  to  free 
research  from  the  misleading  complexities  of  subjective 
adulterations,  and  view  things  as  they  are  apart  from  their 
appearances  ;  but  this  aim  seemed  illusory  when  Psychol- 
ogy showed  that  Time,  Space,  Matter,  and  Motion  were 
themselves  not  objective  reals  except  in  so  far  as  they 
represented  subjective  necessities ;  and  that,  in  short, 
things  are  just  what  they  appear,  since  it  is  only  in  the 
relation  of  external  reals  to  internal  feelings  that  objects 
exist  for  us. 

5.  Idealism  has  been  the  outcome  of  the  psychological 
method.  It  has  been  of  immense  service  in  rectifying 
the  dualistic  conception,  and  in  correcting  the  mechanical 
conception.  It  has  restored  the  subjective  factor,  winch 
the  mechanical  conception  had  eliminated.  It  has  brought 
into  incomparable  clearness  the  fundamental  fact  that  all 
our  knowledge  springs  from,  and  is  limited  by.  Feeling.  It 
lias  shown  that  the  universe  represented  in  that  knowl- 
edge, can  only  be  a  picture  of  the  system  of  things  as 
these  exist  in  relation  to  our  Sensibility.  But  equally 
with  the  mechanical  conception  it  has  erred  by  incom- 
plete analysis.  For  a  complete  theory  of  the  \miverse, 
or  of  any  one  phenomenon,  those  elementary  conditions 
which  analysis  has  provisionally  set  aside  must  finally  be 
restored.  When  Quality  ir?  replaced  by  Quantity,  this  is 
an  artifice  of  method,  which  does  not  really  correspond 
with  fact.     The  quality  is  the  fact  given  in  feeling,  which 


;'.50  THE  riiYsicAL  basis  of  mind. 

we  analytically  refer  to  quantitative  differences,  but  which 
can  never  be  wholly  resolved  into  them,  since  it  must  be 
presupposed  throughout.  One  color,  for  example,  may  be 
distinguished  fi"om  another  as  having  more  or  fewer  un- 
dulations ;  and  so  we  may  by  abstraction,  letting  drop  all 
qualitative  characters,  make  a  scale  of  undulations  to 
represent  the  scale  of  colors.  But  this  is  an  ideal  fig- 
ment. It  is  the  representation  of  one  series  of  feelings 
by  another  series  of  different  feelings.  No  variation  of 
imdulations  will  really  correspond  with  variation  in  color, 
unless  we  reintroduce  the  suppressed  qualiti/  which  runs 
through  all  color.  Attempt  to  make  one  born  blind  feel, 
or  even  understand.  Color  by  describing  to  him  the  kind 
of  wave-movement  which  it  is  said  to  be,  and  the  vanity 
of  the  effort  will  be  manifest.  Movement  he  knows,  and 
varieties  of  movement  as  given  in  tactile  and  muscular 
sensatioiis  ;  but  no  combination  and  manipulation  of  such 
experiences  can  give  him  the  specific  sensation,  of  Color. 
That  is  a  purely  subjective  state,  which  he  is  incapable 
of  experiencing,  simply  because  one  of  the  essential  fac- 
tors is  absent.  One  set  of  objective  conditions  is  present, 
but  the  other  set  (his  sense-organ)  is  defective.  Without 
the  "  greeting  of  the  spirit "  undulations  cannot  become 
colors  (nor  even  undulations,  for  these  also  are  forms  of 
feeling).  Besides  the  sense-organ  there  is  needed  the 
feeling  of  Difference,  which  is  itself  the  product  of  past 
and  present  feeling.s.  The  reproduction  of  other  colors, 
or  other  shades  of  color,  is  necessary  to  this  perception  of 
difference  ;  and  this  involves  the  element  of  Likeness  and 
Unlikeness  between  what  is  produced  and  reproduced. 
So  that  a  certain  mental  co-operation  is  requisite  even 
for  the  simplest  perception  of  quality.  In  fact,  psycho- 
logical analysis  shows  that  even  Motion  and  Quantity, 
the  two  objective  terms  to  which  subjective  Quality  is 
reduced,  are  themselves  Fundamental  Signatures  of  Feel- 


ANIMAL   AUTOMATISM.  351 

ing  ;*  so  that  here,  as  elsewhere,  it  is  only  by  analytical 
artifice  that  the  objective  can  be  divorced  from  the  sub- 
jective. Matter  is  for  us  the  Felt ;  its  Qualities  are  dif- 
ferences of  Feeling. 

6.  Not  that  this  result  is  to  be  interpreted  as  freeing 
our  Theoretic  Conception  from  its  objective  side,  and 
landing  us  in  Idealism,  which  suppresses  the  real  uni- 
verse. The  denial  of  all  reality  apart  from  our  minds,  is 
a  twofold  mistake:  it  confounds  the  conception  of  general 
relations  with  particular  relations,  declaring  that  because 
the  External  in  its  relation  to  the  sentient  organism  can 
only  be  what  it  is  felt  to  be,  therefore  it  can  have  no 
other  relations  to  other  individual  reals.  This  is  the  first 
mistake.  The  second  is  the  disregard  of  the  constant 
presence  of  the  objective  real  in  every  fact  of  Feeling : 
the  Not-Self  is  emphatically  present  in  every  conscious- 
ness of  Self 

The  legitimate  conclusion  is  neither  that  of  Dualism 
nor  of  Idealism,  but  what  I  have  named  Reasoned  Eealism 
(Prohlems,  Vol.  I.  p.  201),  which  reconciles  Common  Sense 
with  Speculative  Logic,  by  showing  that  although  the 
truth  of  things  (their  Wahrheit)  is  just  what  we  perceive 
in  them  (our  Wahrnchmnng),  yet  their  reality  is  this,  and 
much  more  than  this.  Things  are  what  they  are  felt  to 
he ;  and  what  they  are  thought  to  be,  wlien  thoughts  are 
symbols  of  the  perceptions.  Idealism  declares  that  they 
iire  nothing  hut  this.  It  is  against  this  nothing  hat  that 
(.'ommon  Sense  protests  ;  and  the  protest  is  justified  by 
Keasoned  Eealism,  which,  taking  a  comprehensive  survey 
of  the  facts,  thus  answers  the  idealist :  "  Your  synthesis 
is  imperfect,  since  it  does  not  include  all  the  data  —  nota- 
bly it  excludes  the  fact  of  an  objective  or  Not-Self  ele- 
ment in  every  feeling.     You  may,  conceivably,  regard  the 

*  Not  transcendental  and  a  priori,  as  Kant  teaches  ;  but  immanent  in 
Feeling. 


352  THE   niYSICAL  BASIS   OF   MIND. 

whole  universe  as  nothing  but  a  series  of  changes  in  your 
consciousness ;  but  you  cannot  hope  to  convince  nie  that 
I  myself  am  simply  a  change  in  yourself,  or  that  my 
body  is  only  a  fleeting  image  in  your  mind.  Hence  al- 
though I  conclude  that  the  Not-Self  is  to  you,  as  to  me, 
undivorceable  from  Self,  inalienable  from  Feeling,  in  so 
far  as  it  is  felt,  yet  there  must  nevertheless  be  for  both 
of  us  an  existence  not  wholly  coextensive  with  our  own. 
My  world  may  be  my  picture  of  it ;  your  world  may  be 
your  picture  of  it;  but  there  is  something  common  to 
both  which  is  more  than  either  —  an  existent  which  has 
different  relations  to  each.  Yov,  are  not  me,  nor  is  the 
pictured  Cosmos  mc,  although  I  picture  it.  Looking  at 
you  and  it,  I  see  a  vast  whole  of  which  you  are  a  small 
part ;  and  such  a  part  I  conclude  myself  to  be.  It  is  at 
once  a  picture  and  the  pictured ;  at  once  subjective  and 
objective.  To  me  all  your  modes  of  existence  are  objec- 
tive aspects,  which,  drawing  from  my  own  experience,  I 
believe  to  have  corresponding  subjective  aspects ;  so  that 
your  emotions,  which  to  me  are  purely  physical  facts,  are 
to  you  purely  mental  facts.  And  psychological  analysis 
assures  me  that  oW  physical  facts  are  mental  facts  exp7xssed 
in  objective  terms,  and  mental  facts  are  physical  facts  ex- 
pressed in  subjective  terms. 

7.  But  while  Philosophy  thus  replaces  the  conceptions 
of  Dualism  and  Idealism  by  the  conception  of  the  Two- 
fold Aspect,  the  special  sciences  in  their  analytical  career 
have  disregarded  the  problem  altogether.  The  mechani- 
cal theory  of  the  universe  not  only  simplified  research 
by  confining  itself  solely  to  the  objective  aspect  of  phe- 
nomena, but  by  a  further  simplification  set  aside  all  vital 
and  chemical  relations,  to  deal  exclusively  with  mechani- 
cal relations.  In  ascertaining  the  mathematical  relations 
of  the  planetary  system,  no  elucidation  could  possibly 
be  gained  from  biological  or  chemical  conceptions ;  the 


ANIMAL   AUTOMATISM.  353 

planets  therefore  were  provisionally  strij^ped  of  every- 
thing not  mechanical.  In  systematizing  the  laws  of  mo- 
tion, it  was  necessary  to  disengage  the  abstract  relations 
from  everything  in  any  way  resembling  spontaneity,  or 
extra-mechanical  agency :  Matter  was  therefore,  by  a 
bold  fiction,  declared  to  be  inert,  and  its  Motion  regarded 
as  something  superadded  from  without. 

7«.  And  this  was  indispensable  for  the  construction 
of  those  ideal  laws  which  are  the  objects  of  scientific 
research.  Science,  as  we  often  say,  is  the  systematization 
of  Experience  under  the  forms  of  ideal  constructions. 
Experience  implies  Eeeling,  and  certain  fundamental  Sig- 
natures, all  reducible  to  the  primary  discernment  of  Like- 
ness and  Unlikeness.  Hence  Science  is  first  a  classifica- 
tion of  qualities  or  discerned  likenesses  and  differences ; 
next  a  measurement  of  quantities  of  discerned  likenesses 
and  differences.  Although  measurement  is  itself  a  species 
of  classification,  it  is  distinguished  by  the  adoption  of  a 
standard  unit  of  comparison,  which,  being  precise  and 
unvarying,  enables  us  to  express  the  comparisons  in  pre- 
cise and  unvarying  symbols.  Whether  the  unit  of  length 
adopted  be  an  inch,  a  foot,  a  yard,  a  mile,  the  distance 
of  the  earth  from  the  sun,  or  the  distances  of  the  fixed 
stars,  the  quantities  thus  measured  are  symbols  admit- 
ting of  one  invariable  interpretation.  The  exactness  of 
the  mathematical  sciences  is  just  this  precision  and  in- 
variabiHty  of  their  symbols,  and  is  not,  as  commonly 
supposed,  the  source  of  any  superior  certainty  as  to  the 
facts.  The  classificatory  sciences,  which  deal  with  quali- 
ties rather  than  with  ([uantities,  may  be  equally  certain, 
and  represent  fuller  knoidcdge,  because  involving  more 
varied  feelings,  but  they  cannot  pretend  to  exactness. 
Even  on  the  quantitative  side,  certainty  is  not  identical 
with  exactness.  I  may  be  quite  certain  that  one  block 
of  marble  is  larger  than  another  —  meaning  that  it  affects 

w 


354  THE   PHYSICAL  BASIS   OF   MIND. 

me  more  voluminously  —  but  I  cannot  know  how  mueli 
larger  it  is,  without  interpreting  my  feelings  by  the  stan- 
dard of  quantity  —  the  how-muchness  as  represented  by 
that  standard.  The  immense  advantages  of  exact  meas- 
urement need  not  be  insisted  on.  The  Biological  Sci- 
ences, which  are  predominantly  classificatory,  can  never 
rival  the  Cosmological  Sciences  in  exactness ;  but  they 
may  reach  a  fuller  knowledge ;  and  their  certainty  will 
assume  more  and  more  the  character  of  exactness  as 
methods  of  measurement  are  applied  to  their  classifi- 
cations of  qualities.  The  qualitative  and  quantitative  as- 
pects of  phenomena  are  handled  by  the  two  great  instru- 
ments, Logic  and  Mathematics,  the  second  being  only  a 
special  form  of  the  first.  These  determine  the  general 
conceptions  which  are  derived  from  our  perceptions,  and 
the  whole  constitute  Experience. 

8.  What  is  the  conclusion  to  which  these  considera- 
tions lead  ?  It  is  that  the  separation  of  the  quantitative 
from  the  qualitative  aspect  of  phenomena  —  the  objective 
mechanical  from  the  subjective  psychological  —  is  a  logi- 
cal artifice  indispensable  to  research ;  but  it  is  only  an 
artifice.*  In  pursuance  of  this  artifice,  each  special  science 
must  be  regarded  as  the  search  after  special  analytical 
results ;  and  meanwhile  this  method  should  be  respected, 
and  no  confusion  of  the  boundaries  between  one  science 
and  another  should  be  suffered.  Mechanical  problems 
must  not  be  confused  by  the  introduction  of  biological 
relations.  Biological  problems  must  not  be  restricted  to 
mechanical  relations.  I  do  not  mean  that  the  mechani- 
cal relations  present  in  biological  phenomena  are  not 
to  be  sought,  and,  when  found,  to  be  expressed  in  me- 
chanical terms ;  I  mean  that  such  an  inquiry  must  be 

*  The  reader  will  understand  that  although  mechanical  relations  are 
modes  of  Feeling,  as  all  other  relations  are,  yet  their  aspect  is  exclusively 
objective,  referring  to  objects  ideally  detached  from  subjects. 


ANIMAL   AUTOMATISM.  355 

strictly  limited  to  mechanical  relations.  Subjective  rela- 
tions are  not  to  be  denied,  because  they  are  provisionally 
set  aside,  in  an  inquiry  into  objective  relations ;  but  we 
must  carefully  distinguish  which  of  the  two  orders  we 
are  treating  of,  and  express  each  in  its  appropriate  terms. 
This  is  constantly  neglected.  For  example,  nothing  is 
more  common  than  to  meet  such  a  phrase  as  this :  "  A 
sensory  imjjrcssion  is  transmitted  as  a  ivave  of  motion  to 
the  brain,  and  there  being  transformed  into  a  state  of 
consciousness,  is  again  reflected  as  a  moto7-  impulse." 

The  several  sciences  having  attained  certain  analytical 
results,  it  remains  for  Philosophy  to  co-ordinate  these 
into  a  doctrine  which  will  furnish  general  conceptions 
of  the  AVorld,  JMan,  and  Society.  On  the  analytical  side 
a  mechanical  theory  of  the  universe  might  be  perfected, 
but  it  would  still  only  be  a  theory  of  mechanical  re- 
lations, leaving  all  other  relations  to  be  expressed  in  other 
terms.  We  cannot  accept  the  statement  of  Descartes 
that  Nature  is  a  vast  mechanism,  and  Science  the  uni- 
versal application  of  mathematics.  The  equation  of  a 
sphere,  however  valuable  from  a  geometrical  point  of 
view,  is  useless  as  an  explanation  of  the  nature  and  prop- 
erties of  the  spherical  body  in  other  relations.  And  so 
a  complete  theory  of  the  mechanical  relations  of  the 
organism,  however  valuable  in  itself,  would  be  worthless 
in  the  solution  of  a  biological  problem,  unless  supple- 
mented by  all  that  meclianical  terms  are  incompetent  to 
express. 

9.  The  course  of  biological  speculation  has  l)een  simi- 
lar to  the  cosmological.  It  also  began  with  a  First 
Notion,  which  compendiously  expres.sed  the  facts  of 
Experience.  Nor  can  any  Theoretic  Conception  be  finally 
adopted  wliicli  does  away  with  these  facts,  known  with 
positive  certainty,  and  ])0])ularly  expres.sed  in  the  phrase: 
"  I  have  a  body,  and  a  soul."     We  may  alter  tlic  ])hras(' 


356  THE    PHYSICAL   BASIS    OF   MIND. 

either  into  "  I  am  a  body,  and  I  am  a  soul "  ;  or  into,  "  My 
body  is  only  tlie  manifestation  of  my  soul "  ;  or,  "  ]\Iy  soul 
is  only  a  function  of  my  body*"  ;  but  the  fundamental  ex- 
periences which  are  thus  expressed  are  of  absolute  au- 
thority, no  matter  how  they  may  be  interpreted.  That  1 
have  a  body,  or  am  a  body,  is  not  to  be  speculatively  ar- 
gued away.  That  I  move  my  arm  to  strike  the  man  \\\\o 
lias  offended  me,  or  stretch  out  my  hand  to  seize  the  fruit 
which  I  see,  is  unquestionable ;  that  these  movements 
are  determined  by  these  feelings,  and  are  never  thus 
effected  unless  thus  determined,  is  also  unquestionable. 
Here  are  two  sets  of  phenomena,  having  well-marked 
differences  of  aspect ;  and  they  are  grouped  respectively 
under  two  general  heads.  Life  and  Mind.  Life  is  as- 
signed to  the  physical  organism,  or  Body  —  all  its  phe- 
nomena are  objective.  Mind  is  assigned  to  the  psychical 
organism,  or  Soul  —  all  its  phenomena  are  subjective. 
Although  what  is  called  my  Body  is  shown  to  be  a  group 
of  qualities  which  are  feelings  —  its  color,  form,  solidity, 
position,  motion  —  all  its  physical  attributes  being  what 
is  felt  by  us  in  consequence  of  the  laws  of  our  organiza- 
tion ;  yet  inasmuch  as  these  feelings  have  the  character- 
istic marks  of  objectivity,  and  are  thereby  referred  to 
some  objective  existence,  we  draw  a  broad  line  of  demar- 
cation between  them  and  other  feelings  having  the  char- 
acteristic marks  of  subjectivity,  and  referring  to  ourselves 
as  subjects.  Psychological  analysis  shows  us  that  this 
line  of  demarcation  is  artificial,  only  representing  a  di- 
versity of  aspect ;  but  as  such  it  is  indispensable  to  sci- 
ence. We  cannot  really  separate  in  a  sensation  Avhat 
is  objective  from  what  is  subjective,  and  say  how  much 
belongs  to  the  Cosmos  apart  from  Sensibility,  and  how 
much  to  the  subject  pure  and  simple ;  we  can  only  view 
the  sensation  alternately  in  its  objective  and  subjective 
aspects.     What  belongs  to  extra-mental  existence  in  the 


ANIMAL   AUTOMATISM.  357 

phenomenon  of  Color,  and  what  to  the  "  greeting  of  the 
spirit,"  is  utterly  beyond  human  knowledge:  for  the  ethe- 
real undulations  which  physicists  presuppose  as  the  cos- 
mic condition  are  themselves  subjected  to  this  same 
greeting  of  the  spirit :  they  too  are  ideal  forms  of  sensi- 
ble experiences. 

10.  This  conclusion,  however,  was  very  slowly  reached. 
The  distinction  of  aspects  was  made  the  ground  of  a  cor- 
responding distinction  in  agencies.  Each  group  was  per- 
sonified and  isolated.  The  one  group  was  personified  in 
Spirit  —  an  existent  in  every  respect  opposed  to  Matter, 
which  was  the  existent  represented  in  the  other  group. 
One  was  said  to  be  simple,  indestructible ;  the  other  com- 
pound, destructible.  One  was  invisible,  impalpable,  be- 
yond the  grasp  of  Sense ;  the  other  was  visible,  tangible, 
sensible.  One  was  of  heaven,  the  other  of  earth.  Thus 
a  biological  Dualism,  analogous  to  the  cosmological,  re- 
placed the  First  Notion.  It  was  undermined  by  advances 
in  two  directions.  Psychology  began  to  disclose  that  our 
conception  of  ]\Iatter  was,  to  say  the  least,  saturated  with 
Mind,  its  Atoms  confessedly  being  ideal  figments  ;  and  that 
all  the  terms  by  which  Ave  expressed  material  qualities 
were  terms  which  expressed  modes  of  Feeling ;  so  that 
whatever  remained  over  and  above  this  was  the  unknown 
X,  which  speculation  required  as  a  postulate.  Idealism, 
rejecting  this  postulate,  declared  that  Matter  was  simply 
the  projection  of  Mind,  and  that  our  Body  was  the  olyec- 
tivation  of  our  Soul.  Pliysiology  began  to  disclose  that 
all  tlie  mental  processes  were  (mathematically  speaking) 
functions  of  physical  jjrocesses,  i.  e.  varying  with  the  vari- 
ations of  bodily  states ;  and  this  was  declared  enough  to 
banish  forever  the  conception  of  a  Soul,  except  as  a  term 
simply  expressing  certain  functions. 

11.  Idealism  and  Materialism  are  equally  destructive 
of  Dualism.     The  defects  of  particular  idealist  and  mate- 


358  THE   PHYSICAL  BASIS   OF  MIND. 

rialist  theories  \\e  will  not  here  touch  upon  ;  they  mainly 
result  iVom  defects  of  Method.  Not  suthciently  recogniz- 
in<T  the  primary  fact  testified  by  Consciousness,  namely, 
that  Experience  expresses  both  physical  and  mental 
aspects,  and  that  a  Not-Self  is  everywhere  indissolubly 
interwoven  with  Self,  an  objective  factor  with  a  subjective 
factor,  the  idealist  reduces  Existence  to  a  mere  panorama 
of  mental  states,  and  the  Body  to  a  group  in  this  pano- 
rama. He  is  thus  incapable  of  giving  a  satisfactory  ex- 
planation of  all  the  objective  phenomena  which  do  not 
follow  in  the  same  order  as  his  feelings,  which  manifest  a 
succession  unlike  his  expectation,  and  which  he  cannot 
class  under  the  order  of  his  mental  states  hitherto  expe- 
rienced. He  conceives  that  it  is  the  Mind  which  7j?t- 
scrihcs  the  order  in  Things;  whereas  experience  assures 
us  that  the  order  is  descrihcd,  not  prescribed  by  us :  de- 
scribed in  terms  of  Feeling,  but  determined  by  the  laws 
of  Things,  i.  e.  the  genesis  of  subjective  phenomena  is 
determined  by  the  action  of  the  Cosmos  on  our  Sensibil- 
ity, and  the  reaction  of  our  Sensibility.  He  overlooks 
the  evidence  that  the  mental  forms  or  laws  of  thought 
which  determine  the  character  of  particular  experiences, 
were  themselves  evolved  through  a  continual  action  and 
reaction  of  the  Cosmos  and  the  Soul,  precisely  as  the  laws 
of  organic  action  which  determine  the  character  of  par- 
ticular functions  were  evolved  through  a  continual  adap- 
tation of  the  organism  to  the  medium.  These  immanent 
laws  are  declared  to  be  transcendental,  antecedent  to  all 
such  action  and  reaction. 

A  similar  exclusiveness  vitiates  the  materialist  doctrine. 
Overlooking  the  primary  fact  that  Feeling  is  indissolubly 
interwoven  with  processes  regarded  as  purely  physical 
because  they  are  considered  solely  in  their  objective  as- 
pect, the  materialist  fails  to  recognize  the  operation  of 
psychological  laws  in  the  determination  of  physiological 


ANIMAL   AUTOMATISM.  359 

results ;  he  hopes  to  reduce  Biology  to  a  problem  of  Me- 
chanics.     But  Vitality  and   Sensibility  are  coefficients 
which  must  render  the  mechanical  problem  insoluble,  if 
only  on  the  ground  that  mechanical  principles  have  refer- 
ence to  quantitative  relations,  whereas  vital  relations  are 
qualitative.     His  error  is  the  obverse  of   the  vitalist's 
error.     The  vitalist  imagines  that  the  speciality  of  organic 
phenomena  proves  the  existence  of  a  cause  which  has  no 
community  with  the  forces  operating  elsewhere ;  so,  turn- 
ing his  back  on  all  the  evidence,  he  attempts  to  explain 
organic  phenomena  without   any  aid  from  Physics  and 
Chemistry.     The  materialist,  turning  his  back  on  all  the 
evidence  of  quite  special  conditions  only  found  at  work 
in  living  organisms,  tries  to  explain  the  problem  solely  by 
the  aid  of  Physics  and  Chemistry.     It  is  quite  certain 
that  physiological  and  psychological  problems  are  not  to 
be  solved  if  we  disregard  the  laws  of  Evolution  througli 
Epigenesis.     The  mental  structure  is  evolved,  as  the  phys- 
ical structure  is  evolved.     It  is  quite  certain  that  no  sucli 
evolution  is  visible  in  anorganisms,  nor  will  any  one  sup- 
pose it  to  be  possible  in  machines.     From  the  biological 
point  of  view  we  must  therefore  reject  both  Idealism  and 
Materialism.     We  applaud  the  one  when  it  says,  "  Don't 
confuse  mental  facts  by  the  introduction  of  physical  hy- 
potheses"; and  the  other  when  it  says,  "Don't  darken 
physical  facts  with  metaphysical  mists."     We  say  to  both, 
"  By  all  means  make  clear  to  yourselves  which  aspect  of 
the  phenomena  you  are  dealing  with,  and  express  eacli  in 
its  own  terms.     But  in  endeavoring  to  understand  a  phe- 
nomenon you  must  take  into  account  all  its  ascertainable 
conditions.     Now  these   conditions  are  sometimes  only 
approachable  from  the  objective  side  ;  at  other  times  only 
from  tlie  subjective  side." 

12.   While  it  is  necessary  to  keep  tlie  investigation  of  a 
process  on  its  objective  side,  limited  to  objective  condi- 


3G0  THE   niYSICAL   BASIS   OF   MIXD. 

tions,  and  to  express  the  result  in  objective  terms,  we  must 
remember  that  this  is  an  artifice  ;  above  all,  we  must  re- 
member that  even  within  the  objective  limits  our  analyses 
are  only  provisional,  and  must  be  finally  rectified  by  a 
restoration  of  all  the  elements  we  have  provisionally  set 
aside.  Thus  rectified,  the  objective  interpretation  of  vital 
and  mental  phenomena  has  the  incomparable  advantage 
of  simplifying  research,  keeping  it  fixed  on  physical  pro- 
cesses, instead  of  being  perturbed  by  suggestions  of  met- 
aphysical processes.  And  as  all  physical  investigation 
liaturally  tends  to  reduce  itself  to  a  mechanical  investiga- 
tion, because  Mechanics  is  the  science  of  motion,  and  all 
physical  processes  are  motions,  we  may  be  asked,  Why 
should  not  the  mechanical  point  of  view  be  the  rational 
standing-point  of  the  biologist  ?  Our  answer  is.  Because 
Mechanics  concerns  itself  with  abstract  relations,  and 
treats  of  products  without  reference  to  modes  of  produc- 
tion, i.  e.  with  motions  without  reference  to  all  the  con- 
ditions on  which  they  depend.  Every  physical  change, 
if  expressed  in  physical  terms,  is  a  change  of  position, 
and  is  determined  by  some  preceding  change  of  position. 
It  is  a  movement  having  a  certain  velocity  and  direction, 
which  velocity  and  direction  are  determined  by  the  ve- 
locity and  direction  of  a  force  (a  pressure  or  a  tension) 
compounded  with  the  forces  of  resistance,  i.  e.  counter- 
pressures.  Clearly,  the  nature  of  the  forces  in  operation 
must  be  taken  into  account;  and  it  is  this  which  the 
mechanical  view  disregards,  the  biological  regards.  The 
mechanical  view  is  fixed  on  the  ascertained  adjustment  of 
the  parts,  so  that  the  working  of  the  organism  may  be  ex- 
plained as  if  it  were  a  machine,  a  movement  hei-e  liberat- 
ing a  movement  there.  The  biological  view  includes  this 
adjustment  of  parts,  but  takes  in  also  the  conditions  of 
molecular  change  in  the  parts  on  which  the  adjustment 
dynamically  depends.      Mechanical   actions  may  be  ex- 


ANIMAL  AUTOMATISM.  361 

pressed  as  the  enlargement  or  diminution  of  the  angle  of 
two  levers ;  but  chemical  actions  are  not  tlius  expressible ; 
still  less  vital  and  mental  actions. 

13.  The  organism  is  on  the  physical  side  a  mechanism, 
and  so  long  as  the  mechanical  interpretation  of  organic 
phenomena  is  confined  to  expressing  the  mechanical  prin- 
ciples involved  in  the  mechanical  relations,  it  is  emi- 
nently to  be  applauded.  But  the  organism  is  something 
more  than  a  meclianism,  even  on  the  physical  side ;  or, 
since  this  statement  may  be  misunderstood,  let  me  say, 
what  no  one  will  dispute,  that  the  organism  is  a  mechan- 
ism of  a  very  special  kind,  in  many  cardinal  points  unlike 
all  machines.  This  difference  of  kind  brings  with  it  a 
difference  of  causal  conditions.  In  so  far  as  the  actions 
of  this  mechanism  are  those  of  a  dependent  sequence  of 
material  positions,  they  are  actions  expressible  in  mechan- 
ical terms ;  but  in  so  far  as  these  actions  are  dependent 
on  vital  processes,  they  are  not  expressible  in  mechanical 
terms.  Vital  facts,  especially  facts  of  sensibility,  have 
factors  neither  discernible  in  machines  nor  expressible  in 
mechanical  terms.  We  cannot  ignore  them,  although  for 
analytical  purposes  we  may  provisionally  set  them  aside. 

In  the  course  of  the  development  of  the  mechanical 
theory,  the  history  of  wliich  has  just  been  briefly 
sketched,  biological  problems  have  more  and  more  come 
under  its  influence.  There  has  always  been  a  fierce  re- 
sistance to  the  attempt  to  explain  vital  and  sentient 
phenomena  on  mechanical,  or  even  physical  principles, 
but  still  tlic  question  has  incessantly  recurred,  TIow  far 
is  tlie  organism  mechanically  interpretable  ?  And  while 
the  progress  of  Biology  has  shown  more  and  more  the 
machine-like  adjustment  of  the  several  parts  of  whicli 
the  organism  is  composed,  it  has  also  shown  more  and 
more  the  intervention  of  conditions  not  mechanically  iu- 

VOL.  III.  16 


362  THE  rnYsiCAL  basis  of  mind. 

terpretable.  We  shall  have  to  consider  the  question, 
therefore,  under  two  forms.  First,  whether  animals  are 
machines,  and  if  not,  by  what  characters  do  we  distin- 
guish them  from  machines  ?  Secondly,  in  what  sense 
can  we  correctly  speak  of  Feeling  as  an  agent  in  organic 
processes  ? 


ANIMAL  AUTOMATISM.  363 


CHAPTEK    II. 

THE  VITAL  MECHANISM. 

14.  No  answer  can  be  successfully  attempted  in  reply 
to  the  first  of  the  questions  which  closed  the  last  chapter 
until  we  have  given  precision  to  certain  terms  of  inces- 
sant recurrence.  I  have  often  to  remark  on  the  peculiar 
misfortune  of  Psychology,  that  all  its  principal  terms  are 
employed  by  different  writers,  and  are  understood  by  dif- 
ferent readers,  in  widely  different  senses :  they  denote  and 
connote  meanings  of  various  significance.  All  physicists 
mean  the  same  thing  when  they  speak  of  weight,  mass, 
momentum,  electricity,  heat,  etc.  All  chemists  mean  the 
same  thing  when  they  speak  of  affinity,  decomposition, 
oxygen,  carbonic  acid,  etc.  All  physiologists  mean  the 
same  thing  when  they  speak  of  muscle,  nerve,  nutrition, 
secretion,  etc.  But  scarcely  any  two  psychologists  mean 
precisely  the  same  thing  when  they  speak  of  sensation, 
feeling,  thought,  volition,  consciousness,  etc. ;  and  the  dif- 
ferences of  denotation  and  connotation  in  their  uses  of  such 

\  terras  lead  to  endless  misunderstanding.     As  Pousseau 

\  says:  "Les  definitions  pourraient  etre  bonnes  si  Ton  n'em- 

\ployait  pas  les  mots  pour  les  faire."     Put  since  we  must 

employ  words  as  our  signs,  our  utmost  care  should  be 

given  to  clearly  marking  what  it  is  tlie  signs  signify. 

15.  The  ([uestion  wo  have  now  before  us,  whetlicr  ani- 
mal actions  are  interpretable  on  purely  mechanical  ]")rin- 
ciples  ?  can  only  be  answered  after  a  preliminary  settle- 
ment of  the  terms.     The  first  of  tlicsc  terms  to  be  settlfnl 


3G4  THE  niYSICAL   BASIS   OF  MIND. 

is  that  of  mechanism,  when  applied  to  the  vital  organism. 
If  the  organism  is  a  mechanism,  its  actions  must  of 
course  be  interpretable  on  mechanical  principles.  But 
this  general  truth  requires  a  special  interpretation,  if  on 
inquiry  "sve  find  that  the  organism  is  a  particular  kind 
of  mechanism,  one  which  is  not  to  be  classed  under  the 
same  head  as  inorganic  machines.  And  this  we  do  find. 
In  Problem  I.  §  22,  will  be  found  a  statement  of  the 
radical  difference  between  organic  and  inorganic  mechan- 
isms, due  to  the  differences  in  their  structures.  But  the 
differences  there  noted  do  not  affect  the  operation  of  ab- 
stract mechanical  principles,  which  are  of  course  mani- 
fested ivherever  there  is  a  dependent  sequence  of  material 
changes;  and  which  are  the  same  abstract  principles  in  the 
mechanism  of  the  heavens,  the  mechanism  of  a  paper- 
mill,  or  the  mechanism  of  an  animal  body.  In  other 
words,  the  principles  are  abstract,  and  are  abstracted  from 
all  concrete  cases  by  letting  drop  what  is  special  to  each 
case,  retaining  only  what  is  common  to  all.  This  proce- 
dure is  indispensable  to  the  ideal  constructions  of  Science. 
But  we  cannot  rightly  interpret  any  concrete  case  by  ab- 
stract principles  alone ;  we  must  restore  the  special 
characters  which  the  abstraction  has  eliminated.  The 
most  lucid  explanation  of  the  mechanism  of  the  heavens 
will  leave  us  quite  in  the  dark  respecting  the  action  of  a 
paper-mill,  until  we  have  studied  the  mill  at  work,  ascer- 
tained its  structure  and  mode  of  operation,  and  therein 
detected  what  is  common  both  to  its  mechanism  and  to  the 
mechanism  of  the  heavens.  Thus  equipped,  we  approach 
the  study  of  the  animal  mechanism,  l)ut  find  ourselves 
wholly  in  the  dark  until  we  have  also  ascertained  its 
structure  and  mode  of  operation ;  then  we  may  recognize 
in  it  the  principles  of  dependent  sequence  wliich  had 
been  abstracted  from  the  paper-mill  and  the  heavens. 
To  neglect  this  concrete  study,  and  to  argue  from  Ma- 


ANIMAL  AUTOMATISM.  365 

cliinery  to  Life  in  disregard  of  special  conditions,  is  not 
more  rational  than  to  assume  that  the  movement  of  a 
piston  is  prompted  by  volition. 

16.  The  recognition  of  special  differences  is  no  denial 
of  fundamental  identities.  We  do  not  deny  the  presence 
of  phenomena  in  organisms  which  belong  to  physical  and 
chemical  agencies,  but  we  assert  that  organisms  have 
other  phenomena  besides  these,  dependent  on  conditions 
not  present  in  physical  and  chemical  phenomena.  The 
same  material  elements  and  forces  may  be  recognized  in 
a  moving  inorganic  body,  and  a  moving  organic  body  ;  but 
in  the  latter  there  is  a  speciality  of  combination  with  a 
speciality  of  result.  Just  as  the  same  words  and  laws  of 
grammatical  construction  may  be  recognized  in  prose  and 
poetry ;  yet  poetry  is  not  prose,  but  has  special  rules  of 
its  own,  and  special  effects.  In  an  organism,  as  in  a 
machine,  the  adjustment  of  the  parts  is  a  condition  of 
the  meclianical  action ;  the  one  enables  us  to  explain  the 
other.  But  the  parts  adjusted,  and  the  consequences  of 
the  adjustment,  are  unlike  in  the  two  cases.  This  unlike- 
ness  is  pervading  and  profound.  One  cardinal  difference 
is  that  the  combination  of  the  parts  is  in  the  machine  a 
fixed,  in  the  organism  a  fluctuating  adjustment;  and  this 
fkictuation  is  due  to  certain  vital  processes  subjectively 
known  as  sensitive  guidance.  Hence  machines  have  fixed 
and  calculated  mechanisms ;  whereas  organisms  are  varia- 
ble and  to  a  great  extent  incalculable  meclianisms. 

17.  I  conceive,  therefore,  that  a  theory  which  reduces 
vital  activities  to  purely  physical  processes  is  self-con- 
demned. Not  that  we  are  to  admit  the  agency  of  any 
extra-organic  principle,  such  as  the  hypothesis  of  Vital- 
ism assumes  (Prob.  I.  §  14) ;  but  only  the  agency  of  an 
intra-organlc  principle,  or  the  abstract  symbol  of  all  the 
co-operant  conditions  —  the  special  combination  of  forces 
which  result  in  organization.     This  assures  us  that  an 


366  THE   PHYSICAL  BASIS   OF  MIND. 

organism  is  a  peculiar  kind  of  mechanism,  the  processes  in 
which  are  peculiar  to  it ;  and  among  those  processes  there 
is  one  Avhich  results  in  what  we  call  Sensibility.  This 
Sensibility  is  a  factor  which  raises  the  phenomena  into 
another  order.  To  overlook  its  presence  is  fatal  to  any 
explanation  of  the  organic  mechanism.  Yet  it  is  over- 
looked by  those  who  tell  us  that  when  an  impression  on 
a  nerve  is  conveyed  to  the  brain,  and  is  thence  reflected 
on  the  limbs  —  as  when  the  retina  of  a  wolf  is  stimulated 
by  the  image  of  a  sheep,  and  the  spring  of  the  wolf  upon 
the  sheep  follows  as  a  "  purely  mechanical  consequence^ 
the  whole  process  has  from  first  to  last  been  physical." 
Unless  the  term  'pliysical  is  here  used  to  designate  the 
objective  sequence,  as  contemplated  by  an  onlooker,  who 
likens  the  process  to.  the  sequence  observable  in  a  ma- 
chine, I  should  say  that  from  first  to  last  the  process  has 
been  not  physical,  but  vital,  involving  among  its  essential 
conditions  the  peculiarly  vital  factor  named  Sensibility. 
The  process  taking  place  in  the  wolf's  organism  is  one 
which  involves  conditions  never  found  in  purely  physical 
processes.  We  may  indeed  analytically  disregard  these. 
We  may  view  the  process  in  its  purely  physical  relations, 
or  in  its  purely  chemical  relations,  or  in  its  purely  mathe- 
matical (mechanical)  relations.  But  this  is  the  artifice  of 
the  analytical  method.  In  reality  the  process  is  no  one 
of  these,  for  it  is  all  of  these  ;  it  is  a  process  in  a  living 
organism,  and  depends  on  conditions  only  found  in  living 
organisms  —  nay,  in  this  particular  case  the  process  de- 
pends on  conditions  only  found  in  organisms  like  that  of 
the  wolf;  for  the  image  of  the  sheep  will  stimulate  the 
brain  of  a  goat,  horse,  or  elephant  without  producing  any 
such  movement  in  the  organism. 

18.  The  importance  of  this  point  must  excuse  my  re- 
iteration of  it.  We  must  make  clear  to  ourselves  that 
the  organism  is  in  its  objective  aspect  a  physiological 


ANIMAL  AUTOMATISM.  367 

mechanism,  in  its  subjective  aspect  a  psychological  mech- 
anism :  in  both  aspects  it  is  to  be  radically  demarcated 
from  all  inorganic  mechanisms.  In  it  the  combination 
and  co-ordination  of  movements  involve  conditions  never 
present  in  machines ;  among  these  conditions,  there  are 
combinations  and  co-ordinations  of  Sensibility,  which, 
although  material  processes  on  the  objective  side,  are 
processes  believed  to  be  only  present  in  organisms.  We 
have  the  strongest  reasons  for  concluding  that  every  feel- 
ing, every  change  in  Sensibility,  has  its  correlative  ma- 
terial process  in  the  organism — is,  in  short,  only  the 
subjective  aspect  of  the  objective  organic  change.  What 
in  Physiology  is  called  Co-ordination  and  has  reference 
to  movements,  in  Psychology  may  be  called  Logic,  having 
reference  to  feelings.  But  be  this  latter  point  accepted 
or  rejected,  the  one  point  which  admits  of  no  dispute  is 
that  an  organism  is  radically  distinguishable  from  every 
inorganic  mechanism  in  that  it  acquires  through  the  very 
exercise  of  its  primary  constitution,  a  new  constitution  with 
new  powers.  Its  adjustment  is  a  changing  and  developing 
mechanism.  That  is  to  say,  a  machine,  however  complex 
its  structure,  is  constructed  once  for  all,  and  tliis  primary 
constitution  is  final,  the  adjustment  of  parts  remaining 
unaltered ;  and  although  by  exercise  the  machine  may 
come  to  work  more  easily,  with  less  friction,  it  never 
comes  to  work  differently,  to  readjust  its  parts,  and  develop 
new  capabilities.  It  lias  no  historical  factor  manifest  in 
its  functions.  It  has  no  experience.  It  reacts  at  last  as 
at  first,  llow  different  the  organism  !  This  has  not  only 
variable  adjustments  due  to  internal  fluctuations,  it  has 
experience  wliicli  develops  new  parts,  and  new  adjust- 
ments of  old  parts.  Every  organism  has  its  primary  con- 
stitution in  tlie  adjustment  of  parts  peculiar  to  the  spe- 
cies ;  it  has  also  its  secondary  or  moditied  constitution,  in 
the  adjustment  whicli  has  been  more  or  less  altered  by 


308  THE  PHYSICAL  basis  of  mind. 

individual  experiences  ;  it  has,  thirdly,  its  temporary  con- 
stitution in  the  variable  adjustment  due  to  the  varying 
state  of  tension  which  results  from  varying  stimulation. 

19.  A  word  on  each.  There  is  a  structural  disposition 
of  the  parts  which  is  common  to  large  groups  of  organ- 
isms, so  that  a  corresponding  similarity  is  observable  in 
the  reactions  of  these  organisms.  Thus  all  quadrupeds 
use  their  limbs  for  locomotion  in  very  similar  ways  ;  birds 
use  their  wings  for  flight  in  similar  ways.  All  vertebrates 
swallow  their  food,  defend  themselves,  shrink  when  hurt, 
etc.,  in  ways  that  are  very  similar.  In  so  far  as  their 
organizations  are  alike,  their  actions  and  reactions  are 
alike.  In  so  far  as  their  organizations  differ,  their  actions 
and  reactions  differ.  The  goose  and  the  vulture  are  alike 
in  the  main  lines  of  structure ;  still  more  alike  are  duck 
and  hen  :  yet,  owing  to  certain  unlike  characters  of  struc- 
ture, they  manifest  some  marked  differences  in  action  and 
reaction :  the  goose  will  starve  in  the  presence  of  food 
which  the  vulture  gluttonously  devours,  and  the  vulture 
will  refuse  the  vegetable  food  which  the  goose  devours ; 
the  duck  plunges  into  the  water,  the  hen  not  only  refuses 
to  enter  it,  but  is  greatly  agitated  when  she  sees  the  duck- 
lings she  has  hatched  plunging  into  it.  That  peculiar 
instincts,  habits,  and  feelings  are  rigorously  determined 
by  peculiarities  in  the  organism,  no  one  doubts,  when 
animals  are  in  question.  If  this  is  less  obvious  in  the 
case  of  men,  the  reason  is  that  there  the  influence  of  other 
factors  somewhat  masks  the  operation  of  the  primary  con- 
stitution—  these  factors  are  the  modified  and  the  tem- 
porary constitutions.  Yet  even  in  man  it  is  true  to  say 
that  his  feelings  and  actions  are  the  result  of  his  organiza- 
tion, native  and  acquired. 

20.  No  two  men  are  organized  in  all  respects  alike. 
There  are  individual  variations  in  structure,  both  native 
and  acquired.     These  may  be  too  slight  to  be  appreciable 


ANIMAL  AUTOMATISM.  369 

1  ly  any  other  test  than  the  difference  of  reaction  under  simi- 
lar external  stimuli ;  but  the  variations  in  the  sensibility 
to  music,  color,  temperature,  sexual  influence,  moral  in- 
lluence,  etc.,  betray  corresponding  differences  in  the  organ- 
isms. Any  one  variation  in  structure,  seemingly  trivial, 
may  be  the  origin  of  well-marked  diversity  in  physical 
and  moral  characters.  Compare  the  bull  with  the  ox,  or 
the  predatory  aggressive  eagle  with  the  cowardly  vulture. 
Nor  are  the  temporary  modifications  to  be  overlooked. 
Antoine  Cros  mentions  the  case  of  a  patient,  a  young  girl, 
suffering  from  congested  liver  and  spleen,  which  of  course 
altered  the  state  of  her  blood,  and  thus  for  a  time  modi- 
fied her  constitution.  Her  moral  character  was  <^Teatly 
altered  by  it.  She  ceased  to  feel  any  affection  for  father 
(jr  mother ;  would  play  with  her  doll,  but  could  not 
be  brought  to  show  any  delight  in  it ;  could  not  be 
drawn  out  of  her  apathetic  sadness.  Things  Avhich  pre- 
viously had  made  her  shriek  with  laughter,  now  left  her 
uninterested.  Her  temper  changed,  became  capricious 
and  violent.*  Congestion  of  the  lungs,  if  unaccompanied 
])y  congestion  of  the  liver,  never  produces  such  effects,  be- 
cause not  thus  altering  the  blood.  The  effects  of  liver 
congestion  are  familiar.  Cros  cites  the  case  of  a  magis- 
trate whose  liver  was  enlarged,  and  whose  skin  showed  a 
markedly  bilious  aspect,  and  in  whom  all  affection  seemed 
to  be  dead  :  he  did  not  exhibit  any  perversion  or  violence, 
only  want  of  emotive  reaction.  If  he  went  to  the  theatre 
lie  could  not  feel  the  slightest  pleasure  in  it.  The  thoughts 
of  his  home,  his  absent  wife  and  children,  were,  he  de- 
clared, as  unaffecting  to  him  as  a  problem  in  Euclid. 

21.  Owing  to  the  recognized  dependence  of  peculiar  in- 
.stincts  and  modes  of  reaction  on  peculiarities  of  structure, 
comparative  anatomists  are  quite  confident,  when  they 

*  Antoine  Cros,  Lcs  Fond  ions  mpiricurcs  die  SysUmc  ncrvcux,  187j, 
\>.  So.    ■ 

16*  X 


370  THE  PHYSICAL  basis  of  mind. 

find  a  portion  of  a  skull  with  two  occipital  condyles,  that 
the  animal  to  which  this  skull  belonged  had  red  blood- 
cori)uscles  without  nuclei,  and  (if  a  lemale)  suckled  its 
young.  If  in  that  fragment  of  skull  there  remain  a  single 
tooth,  it  will  prove  that  the  animal  was  carnivorous  or 
herbivorous,  and  had,  or  had  not,  retractile  claws.  From 
such  data  a  general  conclusion  may  be  formed  as  to 
the  instincts  and  habits  of  the  animal.  The  data  dis- 
close much  of  the  primary  constitution,  that  is  to  say, 
the  mechanism  which  the  animal  brought  with  it  into  the 
world,  ready  prepared  to  react  in  definite  ways  on  being 
stimulated.  The  connate  mechanism  has  correlative  ten- 
dencies of  reaction.  Some  of  these  tendencies  are  inevi- 
tably called  into  play  by  external  conditions,  and  they 
continue  unaltered  amid  great  varieties  of  circumstances, 
provided  none  of  these  variations  directly  deprive  them 
of  their  appropriate  stimulation.  Such  tendencies  of  the 
connate  mechanism  are  styled  automatic  (an  unfortunate 
metaplior,  which  has  led  to  the  theory  of  Automatism), 
and  include,  besides  the  visceral  reactions,  the  more  com- 
plex reactions  of  winking,  breathing,  swallowing,  cough- 
ing, flying,  walking,  etc.  It  is  true  that  we  learn  to  walk, 
and  learn  to  wink,  whereas  the  other  actions  require  no 
tentative  efforts  directed  by  experience  ;  but  the  mechan- 
ism of  all  these  actions  is  already  laid  down  in  the  pri- 
mary constitution,  and  is  inevitably  called  into  play. 

22.  The  instincts  also  belong  to  the  connate  mechan- 
ism, and  in  the  course  of  the  normal  experience  of  the 
animal  inevitably  come  into  play ;  but,  unlike  the  auto- 
matic tendencies  of  breathing,  swallowing,  and  coughing, 
they  are  capable  of  modification,  or  even  suppression,  by 
alterations  in  the  course  of  individual  experience.  The 
connate  mechanism  of  the  cat  determines  its  dread  of 
water,  and  its  enmity  to  the  dog  and  mouse ;  yet  a  cat 
will  by  the  modifications  of  certain  experiences  become  as 


ANIMAL   AUTOMATISM.  371 

ready  as  an  otter  to  take  to  the  water,  and  become  so 
fond  of  a  dog  that  she  will  allow  him  to  tend  upon  her 
kittens ;  and  so  indifferent  to  the  mouse  that  she  will  let 
it  run  over  her  body.  All  this  implies  a  new  adjustment 
in  the  nefvous  centres,  with  new  modes  of  reaction  on 
sensory  impressions :  the  inherited  mechanism  has  been 
modified.  I  need  not  dwell  on  the  profound  modifica- 
tions which  the  human  inherited  mechanism  undergoes 
in  the  course  of  experience  —  how  social  influences  and 
moral  and  religious  teachings  redirect,  or  even  suppress, 
many  primary  tendencies;  so  that  "moral  habits"  become 
organized,  and  replace  the  original  tendencies  of  the  organ- 
ism. These,  when  organized,  become  the  inevitable  modes 
of  reaction,  and  are  sometimes  called  secondarily  auto- 
matic. It  is  important  to  recognize  this  organization  of 
experiences,  this  acquisition  of  a  secondary  or  modified 
constitution,  if  we  would  explain  psychological  processes 
by  physiological  processes.  Tlius  the  processes  of  Logic 
are  automatic,  they  belong  to  the  connate  primary  mech- 
anism, and  their  action  is  inevitable,  invariable.  The 
elements  of  a  judgment,  like  tlie  elements  of  a  perception, 
may  vary,  and  we  therefore  say  that  one  judgment  is 
false,  and  one  perception  incomplete ;  but  the  judging 
process  is  always  the  same,  and  the  perceiving  process  is 
always  the  same.  We  may  breathe  pure  air  or  impure 
air,  but  the  breathing  process  is  in  each  case  the  same ; 
and  judgment  is  as  automatic  as  breathing,  not  to  be 
altered,  not  to  be  suppressed.  Again,  tlie  moral  terror  at 
wickedness  of  any  recognized  kind  is  as  automatic  as  the 
instinctive  terror  at  danger.  The  one  lias  its  roots  in 
the  primary  disposition  called  love  of  approbation  and  its 
correlative  dread  of  disapprobation :  the  social  instinct. 
The  other  has  its  root  in  the  primary  disposition  called 
"instinct  of  self-preservation,"  whicli  is  really  the  reflex 
shrinking  from  pain  :  tlie  physiological  instinct. 


diJ,  THE   PHYSICAL   BASIS   OF    MIND. 

23.  Besides  the  connate  and  acquired  mechanism,  we 
have  now  to  consider  the  temjiorary  and  H actuating  ad- 
justments which  represent  the  statical  condition  of  the 
organism  at  each  moment.  The  automatism  of  the  pri- 
mary constitution  is  such  that  previous  experience  and 
conscious  effort  are  not  needed ;  nor  will  any  experience 
or  any  effort  alter  the  mode  of  reaction.  If  a  strong 
light  falls  on  the  eye,  the  iris  contracts ;  if  the  eyeball 
is  dry,  the  eyelid  drops ;  if  sound-waves  beat  upon  the 
tympanum,  the  stapedius  muscle  contracts ;  if  the  lin- 
ing of  the  throat  be  tickled,  the  muscles  involved  in 
coughing  or  in  vomiting  contract.  No  experience  is 
necessary  for  these  actions,  some  of  which  are  so  com- 
plicated that  if  we  had  to  learn  them,  as  we  learn  far 
simpler  actions,  the  organism  would  perish  before  the 
power  was  attained.  Yet  all  of  these  presuppose  a  cer- 
tain normal  state  of  the  mechanism,  any  considerable 
variation  in  which  will  modify  or  suppress  them. 

24.  Secondarily  automatic  actions  are  those  which  have 
been  acquired  through  experiences  that  have  modified 
the  organism,  and  produced  a  new  adjustment  of  parts. 
We  learn  to  shield  the  eyes  against  a  strong  glare  of  light 
by  raising  the  hand ;  by  winking  we  learn  to  shield  the 
eye  against  an  approaching  body ;  we  also  learn  to  turn 
the  head  in  tlie  direction  of  a  sound,  and  to  thrust  away 
with  our  hands  the  object  that  is  irritating  our  skin. 
Experience  has  been  necessary  for  all  these  actions,  and 
has  finally  organized  the  tendencies  to  perform  them,  so 
that  the  reaction  is  invariable,  inevitable,  unless  controlled 
by  the  will.  If  you  tickle  my  throat,  I  may,  or  may 
not,  push  aside  your  hand ;  but  if  the  inside  of  my  throat 
be  tickled,  I  must  cough.  Here  we  see  the  difference 
between  the  automatic  and  secondarily  automatic  actions. 
The  second  being  due  to  individual  experience,  are  more 
or  less  controllable ;  and  whether  they  are  or  are  not 


ANIMAL   AUTOMATISM.  37S 

controlled  depends  on  the  condition  of  the  nerve-centres 
at  the  moment.  You  may  tickle  my  throat,  or  irritate 
my  skin,  without  causing  any  movement  of  my  hands  to 
thwart  you,  either  because  my  nerve-centres  are  preoccu- 
pied by  other  stimulations,  and  I  am  not  conscious  of 
the  irritation,  or  because  I  do  not  choose  to  tliwart  you. 

25.  It  should  be  added  that  some  secondarily  auto- 
matic actions  have  become  so  firmly  organized  that  we 
can  only  with  great  difficulty  interfere  with  them.  Others 
never  enter  into  consciousness,  and  are  therefore  often 
supposed  to  be  purely  mechanical.  Tlie  movement  of 
the  eye  towards  the  brightest  light,  and  the  convergence 
of  the  axes  of  both  eyes,  are  reflexes  which,  although 
involuntary  and  unconscious,  are  the  products  of  educa- 
tion. They  do  not  belong  to  the  connate  constitution, 
although  they  are  so  inevitably  acquired  by  experience 
that  they  belong  to  every  normal  child.  At  first  the 
infant  stares  with  a  blank  gaze,  and  its  eyes,  though  mov- 
ing under  the  stimulus  of  light,  move  incoherently ;  the 
axes  never  converge  except  by  accident.  Very  early, 
however,  the  infant's  eyes  are  observed  to  follow  the 
movements  of  a  bright  light ;  and  at  last  they  acqiiire  so 
certain  and  rapid  a  power  of  adjustment  that  the  eyes 
.shift  from  spot  to  spot,  always  "fixing"  the  object  by 
bringing  the  most  sensitive  part  of  the  retina  to  bear  on 
it.  The  incoherent  movements  have  become  precisely 
regulated  movements.  It  is  the  same  with  speech.  The 
vocal  organs  are  exercised  in  an  incoherent  babble.  By 
degrees  these  movements  become  regulated  so  as  to  re- 
spond definitely  to  definite  stimuli,  and  words  are  formed, 
then  sentences,  till  finally  fluent  speech  becomes  in  a 
great  degree  automatic.  The  vocal  muscles  respond  to 
an  auditory  stimulus,  and  the  cliild  repeats  the  word  it 
li.'is  heard,  just  as  the  eye-muscles  respond  to  a  retinal 
stimulus.     That  we  acquire  tlie  power  of  converging  the 


0/4  THE   PHYSICAL   BASIS   OF  MIND. 

axes,  and  accommodating  the  lens  to  near  objects,  is  not 
only  proved  by  observation  of  infants,  but  also  by  cases 
of  disease.  After  the  reliex  mechanism  has  been  Ion"; 
established,  so  that  it  acts  with  inevitable  precision,  a 
slight  paralysis  of  one  of  the  muscles  has  the  effect  of 
making  all  objects  appear  in  a  different  position ;  the 
patient  trying  to  touch  an  object,  then  always  moves  his 
hand  on  one  side  of  it.  Von  Graefe  relates  the  case  of 
a  stonebreaker  who  always  struck  his  hand  with  the 
hammer  when  he  tried  to  strike  the  stone.  Yet  this 
very  man  learned  to  accommodate  his  movements  to  the 
new  impressions ;  so  that  if  his  paralysis  had  been  cured, 
his  modified  mechanism  would  have  been  ill  adapted  to 
the  new  conditions,  and  he  would  once  more  have  struck 
his  hand  instead  of  the  stone. 

26.  This  digression  on  the  native  and  acquired  dispo- 
sitions of  the  organism,  while  it  has  brought  into  strong 
light  all  that  can  be  cited  in  favor  of  regarding  animal 
bodies  as  mechanisms,  and  their  actions  as  the  direct  con- 
sequences of  mechanical  adjustments,  has  also  made  con- 
spicuous the  radical  difference  between  an  organism  and  a 
machine.  We  cannot  too  emphatically  insist  on  this  radi- 
cal difference.  Between  the  group  of  conditions  involved 
in  the  structure  and  action  of  a  machine,  and  the  group 
of  conditions  involved  in  the  structure  and  action  of  an 
organism,  there  are  contrasts  as  broad  as  any  that  can 
be  named.  To  overlook  these  in  taking  account  solely 
of  the  conditions  common  to  both  groups  is  a  serious 
error.  On  such  grounds  we  might  insist  that  a  tiger  is  a 
violet,  because  bolh  are  organisms. 

The  biologist  will  admit  that  an  organism  is  a  mechan- 
ism,  and  (in  so  far  as  its  bodily  structure  is  concerned)  a 
material  mechanism.  All  the  actions  of  this  structure 
are  therefore  mechanical,  in  the  two  senses  of  the  term : 
first,  as  being  the  actions  of  material  adjustments ;  sec- 


ANIMAL  AUTOMATISM.  375 

ondly,  as  being  movements,  and  thereby  included  under 
the  general  laws  of  motion  represented  in  JSIechanics ; 
the  abstract  laws  of  movement  for  an  organic  body  are 
not  different  from  the  abstract  laws  of  movement  for  an 
inorganic  body.  So  far  we  have  been  considering  the 
abstract  relations  only.  No  sooner  do  we  consider  the 
phenomena  as  concrete  wholes,  than  we  find  great  di- 
versity in  the  modes  of  production  of  the  movements  in 
organisms  and  machines.  Now  it  is  precisely  the  modes 
of  production  which  have  interest  for  us.  We  never 
understand  a  phenomenon  so  as  to  gain  any  practical 
control  over  it,  or  any  tlieoretical  illumination  from  it, 
unless  we  have  mastered  some  of  its  conditions ;  our 
knowledge  of  these  conditions  is  the  measure  of  our 
power. 


37G  THE   niYSICAL   BASIS   OF  MIND. 


CHAPTEE   III. 

THE  RELATION   OF  BODY  AND   MIND. 

27.  The  second  question  proposed  was,  In  what  sense 
can  Feeling  be  correctly  spoken  of  as  an  Agent  in  organic 
processes  ?  This  brings  us  face  to  face  with  a  much- 
debated  topic,  the  relation  of  Body  and  Mind;  and  de- 
mands a  theoretic  interpretation  of  that  First  Notion 
which  expresses  universal  experience,  namely,  that  what 
I  know  as  Myself  is  a  Body,  in  one  aspect,  and  a  Soul,  in 
the  other.  What  I  call  my  Body  is  a  persistent  aggre- 
gate of  objective  phenomena ;  and  my  Soul  is  a  persistent 
aggregate  of  subjective  phenomena :  the  one  is  an  indi- 
vidualized group  of  experiences  expressible  in  terms  of 
Matter  and  Motion,  and  therefore  designsited  phi/sical ;  the 
other  an  individualized  group  of  exj)eriences  expressible 
in  terms  of  Feeling,  and  therefore  designated  psT/chical. 
But,  however  contrasted,  they  are  both  simply  embodi- 
ments of  Experience,  that  is  to  say,  are  Modes  of  Feeling. 
All  Existence  —  as  known  to  us — is  the  Felt.  The  laws 
of  our  organism  compel  us,  indeed,  to  postulate  an  Exist- 
ent which  is  extra  meoitem  —  a  Real  not  Ourselves — but 
the  same  laws  debar  us  from  any  knowledge  whatever  of 
what  this  is,  or  is  liJce.  We  know  Things  absolutely  in 
so  far  as  they  exist  in  relation  to  us ;  and  that  is  the 
only  knowledge  which  can  have  any  possible  significance 
for  us. 

28.  It  is  impossible  for  me  to  doubt  that  I  am  a  Body, 
though  I  may  doubt  whether  what  is  thus  called  is  any- 


ANIMAL   AUTOMATISM.  377 

thing  more  than  a  group  of  feelings.  It  is  impossible 
for  me  to  doubt  that  I  am  a  Soul ;  though  I  may  doubt 
whether  what  is  thus  called  is  more  than  a  group  of 
bodily  functions.  In  separating  what  is  unquestionable 
from  what  is  questionable,  we  separate  the  fundamental 
facts  of  consciousness  from  the  theoretic  interpretations 
of  those  facts :  no  theoretic  interpretation  can  efface  or 
alter  the  facts.  Whatever  Philosophy  may  disco^•e^,  it 
cannot  displace  the  fact  that  I  know  I  am  a  Soul,  in  every 
sense  in  which  that  phrase  rep^xscnts  Experience :  I  know 
the  Soul  in  knowing  its  concretes  (feelings),  and  in  know- 
ing it  as  an  abstraction  which  condenses  those  concretes 
in  a  symbol.  The  secondary  question  is,  Whether  this 
abstraction  represents  one  Existent,  and  the  abstraction 
Body  another  and  wliolly  different  Existent,  or  the  two 
abstractions  represent  only  two  different  Aspects  ?  this 
may  be  debated,  and  must  be  answered  according  to  theo- 
retic probabilities. 

29.  What  are  the  probabilities  ?  We  are  all  agreed 
that  Consciousness  is  the  final  arbiter.  Its  primary  de- 
liverance is  simply  that  of  a  radical  distinction.  It  is 
silent  on  the  nature  of  the  distinction  —  says  nothing  as 
to  whether  the  distinction  is  one  of  agents  or  of  aspects. 
It  says,  "  I  am  a  Soul."  With  equal  clearness  it  says,  "I 
am  a  Body."  It  does  not  say,  "  I  am  two  things."  Nor 
does  the  fact  of  a  radical  distinction  imply  more  tlian  a 
contrast  of  aspects,  such  as  that  of  convex  and  concave. 
The  curve  lias  at  every  point  this  contrast  of  convex  and 
concave,  and  yet  is  the  identical  line  tliroughout.  A 
mental  y^rocess  is  at  every  point  contrasted  with  the 
physical  j)rocess  assumed  to  be  its  correlate ;  and  this 
contrast  demands  equivalent  expression  in  the  terms  of 
each.  The  identity  underlying  the  two  aspects  of  the 
curve  is  evident  to  Sense.  The  identity  underlying  the 
mental   and   physical   process  is  not  evident  to   Sense, 


07S  THE   PHYSICAL   BASIS   OF   MIND. 

but  may  be  made  eminently  2^'obahlc  to  Speculation, 
especially  when  we  have  explained  the  grounds  of  the 
ditrerence,,  namely,  that  they  are  apprehended  through 
different  modes.  But  although  I  admit  that  the  conclu- 
sion is  only  one  of  probability,  it  is  one  which  greatly 
transcends  the  probability  of  any  counter- hypothesis. 
Let  us  see  how  this  can  be  made  out.* 

30.  "We  start  from  the  position  that  a  broad  line  of 
demarcation  must  be  drawn  between  the  mental  and  the 
physical  aspect  of  a  process,  supposing  them  to  be  iden- 
tical in  reality.  Nothing  can  be  more  unlike  a  logical 
proposition  than  the  physical  process  which  is  its  cor- 
relate; so  that  Philosophy  has  hitherto  been  forced  to 
forego  every  attempt  at  an  explanation  of  how  the  two 
can  be  causally  connected:  referring  the  connection  to  a 
mystery,  or  invoking  two  different  agents,  spiritual  and 
material,  moving  on  parallel  lines,  like  two  clocks  regu- 
lated to  work  simultaneously.  But  having  recognized 
this  difference,  can  we  not  also  discern  fundamental  re- 
semblances ?  First  and  foremost,  we  note  that  there  is 
common  to  both  the  basis  in  Feeling:  they  are  both  modes 
of  Consciousness.  The  Mind  thinking  the  logical  propo- 
sition is  not,  indeed,  in  the  same  state  as  the  Mind  pic- 
turing the  physical  process  which  is  the  correlate  of  that 
logical  proposition  —  no  more  than  I,  who  see  you  move 
on  being  struck,  have  the  same  feelings  as  you  who  are 
struck.  But  the  ]\Iind  which  pictures  the  logical  proposi- 
tion as  a  process,  and  pictures  the  physical  process  as  a 
bodily  change,  is  contemplating  one  and  the  same  event 
under  its  subjective  and  objective  aspects;  just  as  when  I 

*  The  solution  offered  in  the  present  chapter  was  first  offered  in  Prob- 
lems of  Life  and  Mind,  1875,  II.  465,  sq.  I  mention  this  because  .since 
the  publication  of  that  volume  other  writers  have  expressed  the  same 
ideas,  sometimes  using  my  language  and  illustrations  :  e.  g.  M.  Taine 
in  the  Revue  Philosophiquc,  January,  1877,  art.,  Les  Vibrations  cerebralcs 
ct  la  Pensee. 


ANIMAL  AUTOMATISM.  379 

picture  to  myself  the  feelings  you  experience  on  being 
struck  I  separate  the  subjective  aspect  of  the  blow  from 
its  objective  aspect.  Secondly,  between  the  logical  propo- 
sition and  the  physical  process  there  is  a  con!munity  of 
causal  dependence,  i.  e.  the  mode  of  grouping  of  the 
constituent  elements,  whereby  this  proposition,  and"  not 
another,  is  the  result  of  this  grouping,  and  not  another. 
In  fact,  what  in  subjective  terms  is  called  Logic,  in  objec- 
tive terms  is  Grouping. 

31.  Let  us  approach  the  question  on  a  more  accessible 
side.  Sensation  avowedly  lies  at  the  basis  of  mental 
manifestations.  Now,  rightly  or  wrongly.  Sensation  is 
viewed  alternately  as  a  purely  subjective  fact  —  a  psycho- 
logical process  —  and  as  a  purely  objective  fact — the 
physiological  reaction  of  a  sense-organ.  It  is  so  con- 
spicuously a  physiological  process  that  many  writers 
exclude  it  from  the  domain  of  IMind,  assign  it  to  the 
material  organism,  and  believe  that  it  is  explicable  on 
purely  mechanical  principles.  This  seems  to  me  emi- 
nently disputable ;  but  the  point  is  noticed  in  proof  of 
the  well-marked  objective  character  which  tlie  phenome- 
non assumes.  In  this  aspect  a  sensation  is  simply  the 
reaction  of  a  bodily  organ.  The  physiologist  describes 
how  a  stimulus  excites  the  organ,  and  declares  its  reaction 
to  be  the  sensation.  Thus  viewed,  and  expressed  in  terms 
of  Matter  and  IMotion,  there  is  absolutely  notliing  of  that 
subjective  quality  which  characterizes  sensation.  Yet 
without  this  quality  the  objective  process  cannot  be  a 
sensation.  Exclude  Feeling,  and  tlie  excitation  of  the 
auditory  organ  will  no  more  yield  the  sensation  of  Sound 
l)y  its  reaction,  than  the  strings  and  sounding-board  of 
a  piano  when  the  keys  are  struck  will  yield  music  to  a 
deaf  spectator.  Hence  tlie  natural  inference  has  been  that 
inside  tlie  organism  there  is  a  listcmcr :  tlie  Soul  is  said  to 
listen,  transforming  excitation  into  sensation.     This  infer- 


380  THE  PHYSICAL  basis  of  mind. 

ence  only  needs  a  more  systematic  interpretation  and  it 
will  represent  the  biological  theory,  which  demands  some- 
thing more  than  the  reaction  of  the  sensory  organ  — 
namely,  thf,  reaction  of  the  whole  organism  through  the 
sensory  organ.  I  mean,  that  no  organ  isolated  from  the 
organism  is  capable  of  a  physiological  reaction  —  only 
of  a  physico-chemical  reaction ;  and  sensation  depends 
on  (i.9)  the  physiological  reaction.  When  a  sense-organ  is 
stimulated,  this  stimulation  is  a  vital  process,  and  is  raised 
out  of  the  class  of  physico-chemical  processes  by  virtue 
of  its  being  the  indissoluble  part  of  a  complex  whole. 
Interfere  with  any  one  of  the  co-operant  conditions  — 
withdraw  the  circulation,  check  respiration,  disturb  secre- 
tion—  and  the  sense-organ  sinks  from  the  physiological 
to  the  physical  state ;  it  may  then  be  brought  into 
contact  with  its  normal  stimuli,  but  no  stimulation  (in 
the  vital  sense)  will  take  place,  there  will  be  no  vital 
reaction. 

Condensing  all  vital  processes  in  the  symbol  Vitality, 
we  may  say  Vitality  is  requisite  for  every  physiological 
process.  A  parallelism  may  be  noted  on  the  subjective 
side :  all  the  sentient  processes  may  be  condensed  in  the 
one  symbol  Sensibility  (Feeling),  and  we  nmst  then  say, 
No  psychological  process  is  possible  as  an  isolated  fact, 
but  demands  the  co-operation  of  others  —  it  is  a  resultant 
of  all  the  contemporaneous  conditions  of  Sensibility  in 
the  organism.  In  ordinary  language  this  is  what  is  meant 
by  saying  that  no  impression  can  become  a  sensation 
without  the  intervention  of  Consciousness  —  an  ambigu- 
ous phrase,  because  of  the  ambiguity  of  the  term  Con- 
sciousness, but  the  phrase  expresses  the  fact  that  in 
Sensation  a  process  in  the  organism  is  necessary  to  the 
reaction  of  the  organ. 

32.  Having  recognized  the  distinction  between  the  two 
processes  objective  and  subjective,  physical  and  mental. 


ANIMAL  AUTOMATISM.  381 

we  have  recognized  the  vanity  of  attempting  to  assign 
their  limits,  and  to  say  where  Motion  ends  and  Feeling 
begins,  or  how  Feeling  again  cliauges  into  Motion.  The 
one  does  not  begin  where  the  other  ends.  According  to 
the  two-clock  theory  of  Dualism,  the  two  agents  move  on 
parallel  lines.  On  the  theory  of  Monism  the  two  aspects 
are  throughout  opposed.  Both  theories  explain  the  facts  ; 
which  explanation  is  the  most  congruous  with  experience? 
Against  the  first  we  may  object  that  the  hypothesis  of  two 
Agents  utterly  unallied  in  nature  wants  the  cardinal  char- 
acter of  a  fertile  hypothesis  in  its  unverifiableness :  it 
may  be  true,  we  can  never  know  that  it  is  true.  By  the 
very  terms  of  its  definition,  the  Spirit  —  if  that  mean 
more  than  an  abstract  expression  of  sentient  states  —  is 
beyond  all  sensible  experience.  This  is  indeed  admitted 
by  the  dualists,  for  they  postulate  a  Spirit  merely  because 
they  cannot  otherwise  explain  the  plienomena  of  Con- 
sciousness. Herein  they  fail  to  see  that  even  their  pos- 
tulate brings  no  explanation,  it  merely  restates  the  old 
problem  in  other  terms. 

33.  Up  to  the  present  time  these  same  objections  might 
liave  been  urged  with  ecpial  force  against  Monism.  In- 
deed, although  many  philosophers  have  rejected  the  two- 
clock  theory  of  Leibnitz,  they  have  gained  a  very  hesitat- 
ing acceptance  for  their  own  hypothesis  of  identity.  To 
most  minds  the  difficulty  of  imagining  how  a  physical 
process  could  also  be  a  p.sychical  process,  a  movement  also 
be  a  feeling,  seemed  not  less  than  that  of  imagining  how 
two  sucli  distinct  Agents  as  Matter  and  Mind  could  co- 
operate, and  react  on  eacla  otlier,  or  move  simultaneously 
on  parallel  lines.  Although  for  many  years  I  have  ac- 
cepted the  hypotliesis  of  Monism,  I  have  always  recog- 
nized its  want  of  an  ade([uate  reply  to  such  objections. 
Unless  I  greatly  deceive  myself,  I  have  now  found  a  solu- 
tion of  the  main  difficulty  ;  and  found  it  in  psychological 


382  THE  niYsiCAL  basis  of  mind. 

conditions  wliich  are  perfectly  intelligible.  But  knowing 
how  easily  one  may  deceive  one's  self  in  such  matters,  1 
will  only  ask  the  reader  to  meditate  with  open-minded- 
ness  the  considerations  now  to  be  laid  before  him,  and  see 
if  he  can  feel  the  same  confidence  in  their  validity. 

34.  One  of  the  early  stages  in  the  development  of  Expe- 
rience is  the  separation  of  Self  from  the  Not-Self.  I  look 
out  on  "  the  vast  extern  of  things,"  and  see  a  great  variety 
of  objects,  included  in  a  visible  hemisphere.  All  these 
objects  in  various  positions,  having  various  forms  and  col- 
ors, I  believe  to  be  wholly  detached  from,  and  in  every 
way  unallied  to.  Myself.  And  what  is  that  Self '?  It  is 
my  Body  as  a  visible  and  tangible  object,  separated  from 
all  other  visible  and  tangible  objects  by  the  constant  pres- 
ence of  feelings  connected  with  it  and  its  movements,  and 
not  connected  with  the  other  objects.  This  constant  pres- 
ence of  feelings  is  referred  to  a  Soul,  which  I  then  sepa- 
rate from  my  Body,  as  an  Inner  Self;  and  from  this  time 
onwards  I  speak  of  the  Body  as  mine,  and  learn  to  regard 
it  in  much  the  same  light  as  other  outer  objects.  In  my 
naive  judgment  the  external  objects  are  supposed  to  exist 
f(s  I  see  and  touch  them,  whether  I  or  any  one  else  see 
and  touch  them  or  not :  they  in  no  sense  belong  to  the 
series  of  feelings  which  constitute  the  Me.  And  since 
my  Body  resembles  these  objects  in  visible  and  tangible 
qualities,  and  also  in  being  external  to  my  feelings,  it  also 
takes  its  place  in  the  objective  world.  Thus  arises  the 
hypothesis  of  Dualism  which  postulates  a  Physis,  or  ob- 
ject-world, and  an  yEsthcsis,  or  subject-world  :  two  inde- 
pendent existents,  one  contemplated,  the  other  contem- 
plating. 

35.  Philosophy,  as  we  know,  leads  to  a  complete 
reversal  of  this  primitive  conclusion,  and  shows  that  the 
contemplated  is  a  syntlusis  of  contemplations,  the  Physis  be- 
ing also  the  ^sthesis.     Psychological  investigation  shows 


ANIMAL   AUTOMATISM.  383 

that  the  objects  supposed  to  have  forms,  colors,  and  posi- 
tions within  an  external  hemisphere,  have  these  only  in 
■\-irtue  of  the  very  feelings  from  which  they  are  supposed 
to  be  separated.  The  visible  universe  exists  only  as  seen : 
the  objects  are  Eeals  conditioned  by  the  laws  of  Sensi- 
bility. The  space  in  which  we  see  them,  their  geomet- 
rical relations,  the  light  and  shadows  which  reveal  them, 
the  forms  they  affect,  the  lines  of  their  changing  direc- 
tions, the  qualities  which  distinguish  tliem,  —  all  these 
ate  but  the  externally  projected  signs  of  feelings.  They 
are  signs  which  we  interpret  according  to  organized  laws 
of  experience  ;  each  sign  being  itself  a  feeling  connected 
with  other  feelings.  We  project  tliem  outside  according 
to  the  "  law  of  eccentric  projection  "  —  which  is  only  the 
expression  of  the  fact  that  one  feeling  is  a  sign  of  some 
other,  and  is  thereby  ideally  dctaehecl  from  it.  According 
to  this  law  I  say,  "my  Body";  just  as  I  say,  "my 
House  "  ;  or,  "  my  Property."  IMisled  by  this,  Dualism 
holds  that  in  the  very  fact  of  detaching  my  Body  from 
my  Self,  calling  it  mine,  is  the  revelation  of  a  distinct 
entity  within  the  body.  But  that  this  is  illusory,  appears 
in  the  application  of  this  same  law  of  eccentric  projection 
to  sensations  and  thoughts,  which  are  called  mine,  as  my 
legs  and  arms  are  mine.  If  it  is  undeniable  that  I  say 
my  Body  —  and  thus  ideally  detach  the  Body  from  the 
Soul  —  it  is  equally  undeniable  that  I  say  my  Soul ;  and 
from  what  is  the  Soul  detached  ?  In  presence  of  this 
difficulty,  the  metaphysician  may  argue  tliat  neither  Body 
nor  Soul  can  be  coextensive  with  its  manifestations,  but 
demands  a  noumenal  Real  for  each  —  a  substratum  for  the 
bodily  manifestations,  and  a  substratum  for  the  mental 
manifestations.  This,  however,  is  an  evasion,  not  a  solu- 
tion of  the  difficulty.  If  we  postulate  an  unknown  and 
unknowable  noumenon,  we  gain  no  insight :  first,  because 
Pliilosopliy  deals  only  with  the  known  functions  of  un- 


384  THE   PHYSICAL   BASIS   OF   MIND. 

known  quantities,  and  therefore  leaves  the  x  out  of  the 
calculation ;  secondly,  because,  granting  the  existence  of 
these  noumena,  we  can  have  no  rational  grounds  for 
asserting  that  they  are  not  of  one  and  tlie  same  nature  ; 
for  we  have  no  grounds  for  any  assertion  whatever  about 
them.  And  if  it  be  urged  against  tliis,  that  Conscious- 
ness testifies  to  a  distinction,  I  answer  that  on  a  closer 
scrutiny  it  will  be  found  to  testify  to  nothing  more  than 
a  diversity  of  manifestation.  All  therefore  that  comes 
within  the  range  of  knowledge  is,  How  does  this  diversity 
arise  \ 

36.  There  are  two  ways,  and  there  are  only  two,  in 
which  differences  arise.  These  are,  1°,  the  modes  of  pro- 
duction of  a  product,  and,  2°,  our  modes  of  appreliension  of 
the  product.  Things  may  be  very  different,  and  yet  to 
our  apprehension  indistinguishable,  so  that  we  regard 
them  as  identical ;  and  they  may  be  identical,  yet  appear 
utterly  unlike.  A  mechanical  bird  may  seem  so  like  a 
living  bird,  and  their  actions  so  indistinguishable  to  the 
spectator,  that  he  will  not  suspect  a  difference,  or  suspect- 
ing it,  will  not  be  able  to  specify  it.  Of  both  objects,  so 
long  as  his  modes  of  apprehending  them  are  circumscribed, 
he  can  only  say  what  these  imply  :  he  sees  familiar  forms, 
colors,  and  movements,  which  he  interprets  according  to 
the  previous  experiences  of  which  these  are  the  signs. 
But  by  varying  the  modes  of  apprehension,  and  gaining 
thus  a  fuller  knowledge,  he  finds  that  the  two  products 
have  very  different  modes  of  production  ;  hence  he  con- 
cludes the  products  to  be  different :  the  mechanism  of  the 
one  is  not  the  organism  of  the  other ;  the  actions  of  the 
mechanical  bird  are  not  the  actions  of  the  living  bird. 
The  fuller  knowledge  has  been  gained  by  viewing  the  ob- 
jects under  different  relations,  and  contemplating  them  in 
their  modes  of  production,  not  as  merely  visible  products. 
He  sees   the    mechanism    performing  by   steel   sjorings. 


ANIMAL  AUTOMATISM.  385 

wheels,  and  wires,  the  work  which  the  organism  performs 
by  bones,  muscles,  and  nerves  ;  and  tlie  farther  his  anal- 
ysis of  the  modes  of  production  is  carried,  the  greater  are 
the  differences  which  he  apprehends. 

37.  Xow  consider  the  other  side.  One  and  the  same 
object  will  necessarily  present  very  different  aspects  under 
different  subjective  conditions,  since  it  is  tliese  which  de- 
termine the  aspect.  The  object  cannot  be  to  Sight  what 
it  is  to  Hearing,  to  Touch  what  it  is  to  Smell.  The  vibra- 
tions of  a  tuning-fork  are  seen  as  movements,  heard  as 
sounds.  In  current  language  the  vibrations  are  said  to 
cause  the  sounds.  Misled  by  this,  philosophers  puzzle 
themselves  as  to  how  a  material  process  (vibration)  can 
be  transformed  into  a  mental  process  (sensation),  how 
such  a  cause  can  have  so  utterly  different  an  effect.  But 
I  have  formerly*  argued  at  some  length  that  there  is  no 
transformation  or  causation  of  the  kind  supposed.  The 
tuning-fork  —  or  that  Real  which  in  relation  to  Sense  is 
the  particular  object  thus  named  —  will,  by  one  of  its 
modes  of  acting  on  my  Sensibility  through  my  optical 
apparatus,  determine  the  response  known  as  vibrations  ; 
but  it  is  not  this  response  of  the  optical  organ  which  is 
transformed  into,  or  causes  the  response  of  the  auditory 
organ,  known  as  sound.  The  auditory  organ  knows  noth- 
ing of  vibrations,  the  optical  nothing  of  sounds.  The 
responses  are  botli  modes  of  Feeling  determined  by  or- 
ganic conditions,  and  represent  the  two  different  relations 
in  which  the  Eeal  is  apprehended.  The  Real  is  alter- 
nately the  one  and  the  other.  And  if  the  one  mode  of 
Feeling  has  a  physical  significance,  while  the  otlier  has  a 
mental  significance,  so  that  we  regard  tlie  vil)rations  as 
objective  facts,  belonging  to  the  external  world,  and  the 
sounds  as  subjective  facts,  exclusively  belonging  to  the 
internal  world,  this  is  due  to  certain  psychological  influ- 
*  Problems  of  Life  and  Miiid,  Vol.  IT.  pp.  443  and  482. 

VOL.  III.  17  Y 


386  THE   PHYSICAL   BASIS    OF   MIND. 

ences  presently  to  be  expounded.  Meanwhile  let  us  fix 
clearly  in  our  minds  that  both  vibrations  and  sounds  are 
modes  of  Feeling.  My  consciousness  plainly  assures  me 
that  it  is  I  who  see  the  one,  and  hear  the  other ;  not  that 
there  are  two  distinct  subjects  for  the  two  distinct  feel- 
ings. Add  to  which,  manifold  uncontradicted  experiences 
assure  me  that  the  occasional  cause  —  the  objective  factor 
—  of  the  one  feeling,  is  also  the  cause  of  the  other,  and 
not  that  the  two  feelings  have  two  different  occasional 
causes.  From  both  of  these  undeniable  facts  we  must 
conclude  that  the  difference  felt  is  simply  a  difference 
of  aspect,  determined  by  some  difference  in  the  modes  of 
apprehension. 

38.  Assuming  then  that  a  mental  process  is  only  an- 
other aspect  of  a  physical  process  —  and  this  we  shall 
find  the  more  probable  hypothesis  —  we  have  to  explain 
by  what  influences  these  diametrically  opposite  aspects 
are  determined.  From  all  that  has  just  been  said  we 
must  seek  these  in  the  modes  of  apprehension.  There 
can  be  no  doubt  that  we  express  the  fact  in  very  different 
terms  ;  the  question  is,  "What  do  these  terms  signify  ? 
Why  do  we  express  one  aspect  in  terms  of  Matter  and 
Motion,  assigning  the  process  to  the  objective  world;  and 
the  other  aspect  in  terms  of  Feeling,  assigning  the  process 
to  the  subjective  w^orld  ? 

Let  the  example  chosen  be  a  logical  process  as  the 
mental  aspect,  and  a  neural  process  as  its  physical  corre- 
late. The  particular  proposition  may  be  viewed  logically, 
as  a  grouping  of  experiences,  or  physiologically,  as  a  group- 
ing of  neural  tremors.  Here  we  have  the  twofold  aspect  of 
one  and  the  same  reality ;  and  these  different  aspects  are 
expressed  in  different  terms.  We  cannot  be  too  rigorous 
in  our  separation  of  the  terms ;  for  every  attentive  student 
must  have  noted  how  frequently  discussions  are  made 
turbid  by  the  unconscious  shifting  of  terms  in  the  course 


ANIMAL  AUTOMATISM.  387 

of  the  argumentation.  This  is  not  only  the  mistake  of 
opponents  who  are  unaware  of  the  shifting  which  lias 
occurred  in  each  otlier's  minds,  so  that  practically  the 
adversaries  do  not  meet  on  common  ground,  but  cross 
and  recross  each  other ;  it  is  also  the  mistake  of  the  soli- 
tary thinker  losing  himself  in  the  maze  of  interlacing  con- 
ceptions instead  of  keeping  steadily  to  one  path.  Only 
by  such  shifting  of  terms  can  the  notion  of  the  physical 
process  causing,  or  being  tranformed  into,  the  mental 
process  for  a  moment  gain  credit ;  and  this  also  greatly 
sustains  the  hypothesis  of  Dualism,  with  its  formidable 
objections  :  How  can  Matter  think  ?  How  can  Mind  act 
on  Matter  causing  Motion? 

39.  Those  who  recognized  that  the  terms  Matter  and 
j\Iind  were  abstractions  mutually  exclusive,  saw  at  once 
that  these  questions,  instead  of  being  formidable,  were  in 
truth  irrational.  To  ask  if  Matter  could  think,  or  Mind 
move  Matter,  was  a  confusion  of  symbols  equivalent  to 
speaking  of  a  yard  of  Hope,  and  a  ton  of  Terror.  Al- 
though Measure  and  Weight  are  symbols  of  Feeling,  and 
in  this  respect  are  on  a  par  with  Hope  and  Terror,  yet 
because  tliey  are  objective  symbols  they  cannot  be  ap- 
plied to  subjective  states,  without  violation  of  the  very 
significance  they  were  invented  to  express.  No  one  ever 
asks  whether  a  sensation  of  Sound  can  be  a  sensation  of 
Color :  nor  whether  Color  can  move  a  machine,  althoufrh 
Heat  can,  yet  the  one  is  no  less  a  sensation  than  the 
other.  On  similar  grounds  no  one  should  ask  whether 
Matter  can  think,  or  Mind  move  Matter.  The  only 
rational  question  is  one  i)reserving  tlie  integrity  of  the 
terms,  namely,  whether  tlie  living,  tliinking  organism 
presents  itself  to  apprehension  under  the  twofold  a-spect 
—  now  under  the  modes  of  Feeling  classified  as  ol)jective 
or  physical ;  now  under  the  modes  classified  as  subjective 
or  mental. 


388  THE   PHYSICAL  BASIS   OF  MIND. 

40.  We  are  told  that  it  is  "  impossible  to  imagine  Matter 
thinking,"  which  is  very  true ;  only  by  a  gross  confusion 
uf  terms  can  Thought  be  called  a  property  of  cerebral 
tissue,  or  of  Matter  at  all.  We  may,  indeed,  penetrate 
beneath  the  terms  which  relate  to  aspects,  and  recognize 
in  the  underlying  reality  not  two  existences,  but  one. 
Our  conceptions  of  this  reality,  however,  are  expressed  in 
symbols  representing  different  classes  of  feelings,  objec- 
tive and  subjective  ;  and  to  employ  the  terms  of  one  class 
to  designate  the  conceptions  of  the  other  is  to  frustrate 
the  very  purposes  of  language.  Matter  and  Mind,  Ob- 
ject and  Subject,  are  abstractions  from  sentient  experi- 
ences. We  know  them  as  abstractions,  and  know  the 
concrete  experiences  from  which  they  are  abstracted. 
Philosophers,  indeed,  repeatedly  assure  us  that  we  neither 
know  what  Matter  is  nor  what  Mind  is,  we  only  know 
the  2^^icnomenal  pj^oduds  of  the  action  and  reaction  of 
these  two  unknown  noumena.  Were  this  so,  all  dis- 
cussion would  be  idle  ;  we  could  not  say  whether  Matter 
was  or  was  not  capable  of  thinking,  whether  ]\Iind  w^as 
or  w'as  not  the  same  as  Matter,  we  could  only  abstain 
from  saying  anything  whatever  on  the  topic.  What 
should  we  reply  to  one  who  asked  us  to  name  the  pro- 
duct of  two  unknown  quantities  ?  So  long  as  x  and  ?/  are 
without  values  their  product  must  be  without  value.  If 
the  value  of  x  be  known,  and  that  of  y  unknown,  then 
the  product  still  remains  unknown :  x  -{•  y  ='x  -\-  o  =  x. 
Therefore,  unless  the  Objective  aspect  were  the  equivalent 
of  the  Subjective  aspect,  it  could  never  be  subjectively 
present.     Feeling  is  but  another  aspect  of  the  Felt. 

41.  It  is  because  we  do  know  wdiat  Matter  is,  that  we 
know  it  is  not  Mind :  they  are  symbols  of  two  different 
modes  of  Feeling.  If  we  separate  the  conception  of  cit- 
izenship from  the  conception  of  fatherhood,  although  the 
same  man  is  both  citizen  and  father,  how  much   more 


ANIMAL  AUTOMATISM.  389 

decisively  must  we  separate  the  conception  of  Matter, 
which  represents  one  group  of  feelings,  from  the  concep- 
tion of  ]\Iind,  which  represents  another  ?  One  element 
in  the  former  is  common  to  the  whole  group,  namely,  the 
reference  to  a  Not-Self,  induced  by  the  sensation  of  Ee- 
sistance,  which  always  ideally  or  sensibly  accompanies 
the  material  class.  The  axiom,  I  feel,  ergo  I  exist,  has 
its  correlative :  —  I  act,  ergo  there  are  other  existents  on 
which  I  act ;  and  tliese  are  not  wholly  Me,  for  they  re- 
sist, oppose,  exclude  me ;  yet  they  are  also  one  with  Me, 
since  they  are  felt  by  me.  In  my  Feeling,  that  which 
is  not  Me  is  Matter,  the  objective  aspect  of  the  Felt,  as 
Mind  is  the  subjective  aspect. 

But  since  Hunger  and  Thirst,  Joy  and  Grief,  Pain  and 
Terror,  are  also  felt,  yet  are  never  classed  under  the  head 
of  Matter,  the  grounds  of  the  classification  of  feelings 
have  to  be  expressed.  Professor  Bain  makes  the  distinc- 
tion between  Matter  and  Mind  to  rest  solely  on  the  pres- 
ence or  absence  of  Extension :  this  is  the  decisive  mark : 
Matter  he  defines  as  the  Extended.  The  definition  is  in- 
adequate. When  I  see  a  dog  and  its  image  reflected  in  a 
pool,  or  see  a  dog  and  think  of  another,  in  the  three  cases 
dog,  image,  and  idea  have  Extension ;  but  I  recognize  the 
dog  as  a  material  fact,  the  idea  as  a  mental  fact;  and 
although  the  image  of  the  dog  has  material  conditions  by 
which  I  am  optically  affected,  just  as  the  idea  has  ma- 
terial cerebral  conditions,  I  recognize  a  marked  difference 
between  them  and  the  dog,  due  to  the  different  modes  of 
apprehension.  The  dog  is  known  as  a  persistent  reality, 
which,  when  Sight  is  supplemented  by  Touch,  will  yield 
sensations  of  liesistance,  and  thus  disclose  its  materiality. 
The  image  vanishes  if  I  attempt  to  touch  it ;  I  see  its 
outlines  waver  and  become  confused  with  every  disturb- 
ance of  the  surface  of  tlie  pool ;  the  idea  vanishes  when 
another  idea  arises ;  whence  I  conclude  that  neither  has 


390  THE   PHYSICAL  BASIS   OF  MIND. 

material  reality,  because  neither  lias  the  Eesistance  which 
characterizes  the  Not-Self.  The  image  and  the  idea  may 
be  referred  to  material  conditions,  but  so  may  pains,  ter- 
rors, volitions,  yet  these  are  all  without  Extension,  simply 
because  they  are  not  visual  feelings. 

42.  Matter  does  not  represent  all  feelings,  but  only  the 
objective  sensibles ;  and  these  are  not  all  characterized 
by  Extension,  but  only  those  which  directly  or  indirectly 
involve  optico-tactical  experiences  accompanied  by  mus- 
cular experiences.  Matter  is  primarily  the  Visible  and 
Eesistent ;  and  secondarily,  whatever  can  be  imagined  as 
such ;  so  that  ether,  molecules,  and  atoms,  although  nei- 
ther visible  nor  tangible,  are  ranged  under  the  head  of 
Matter.  Color  is  a  feeling  as  Sound  and  Scent  are  feel- 
ings, and  although  material  conditions  are  equally  presup- 
posed in  all  three,  yet  Color  alone  has  Extension,  and  be- 
cause it  can  be  imaged  it  has  a  more  objective  character 
than  the  others,  which  having  no  lines  and  surfaces,  want 
the  optical  conditions  for  the  formation  of  images,  and  are 
less  definitely  connected  with  tactical  and  muscular  expe- 
riences. Nevertheless,  since  Sound  and  Scent  are  obvi- 
ously associated  with  objects  seen  and  touched,  they  have 
a  degree  of  materiality  never  assigned  to  such  feelings  as 
Hunger  and  Thirst,  Pleasure,  Terror,  and  Hope. 

43.  When  we  refer  feelings  to  material  conditions,  we 
follow  the  natural  tendency  to  translate  the  little  known 
in  terms  of  the  better  known,  and  employ  the  symbols 
Matter  and  Motion,  because  these  furnish  the  intellect 
with  images,  i.  e.  definite  and  exact  elements  to  operate 
with.  In  hearing  a  sound,  there  is  nothing  at  all  like 
"vibrations,"  nothing  like  "aerial  waves"  and  "neural 
processes,"  given  in  that  feeling;  but  on  attempting  to 
explain  it,  we  remove  it  from  the  sphere  of  Sensation  to 
carry  it  into  the  sphere  of  Intellect,  and  we  must  change 
our  symbols  in  changing  our  problem ;  here  our  only  re- 


i 


ANIMAL  AUTOMATISM.  391 

source  is  to  translate  the  subjective  state  into  an  imagi- 
nable objective  process,  which  can  only  be  expressed  in 
terms  of  Matter  and  Motion.  What  we  heard  as  Sound 
is  tlien  seen  as  Vibration.  When  we  are  optically  or 
mentally  contemplating  vibrations  and  neural  processes, 
we  are  supplanting  one  source  of  feeling  by  another, 
translating  an  event  in  another  set  of  symbols.  But  we 
can  no  more  hear  the  sound  in  seeing  the  vibrations, 
than  a  blind  man  can  see  the  fly  in  the  amber  whicli  he 
feels  with  his  fingers,  or  than  we  can  feel  the  amber  he 
holds,  while  we  are  only  looking  at  it.  The  j)hrase  "  ma- 
terial conditions  of  Feeling"  sometimes  designates  the 
objective  aspect  of  the  subjective  process,  and  sometimes 
the  agencies  in  the  external  medium  which  co-operate 
w'itli  the  organism  in  the  production  of  the  feelings.  In 
each  case  there  is  an  attempt  to  explain  a  feeling  by  in- 
telligible symbols. 

44.  The  Animal  probably  never  attempts  such  expla- 
nation; satisfied  with  the  facts,  it  is  careless  of  their 
factors.  Man  is  never  satisfied :  is  restless  in  the  search 
after  factors ;  and  having  found  them,  seeks  factors  of 
these  factors ;  so  that  Lichtenberg  felicitously  calls  him 
"das  rastlose  Ursachenthier "  —  "the  animal  untiring  in 
the  search  for  causes."  And  thus  sciences  arise :  we 
translate  experiences  into  geometrical,  physical,  chemical, 
physiological,  and  p.sychological  terms  —  different  sym- 
bols of  the  different  modes  of  apprehending  phenomena. 

45.  "I  see  an  elephant."  In  other  words,  I  am  af- 
fected in  a  certain  way,  and  interpret  my  affection  by 
previous  similar  experiences,  expressing  these  in  verbal 
symbols.  -  But  I  want  an  explanation,  and  tliis  tlio  ])hi- 
losopher  vouchsafes  to  me  by  translating  my  afl'ection 
into  his  terms.  He  takes  me  into  another  sphere  —  tells 
me  of  an  undulating  Ether,  the  waves  of  which  beat 
upon  my  retina  —  of  lines  of  Light  refracted  by  media 


302  THE  niYsiCAL  basis  of  mind. 

and  converged  by  lenses  according  to  geometric  laws  — 
of  the  formation  thereby  of  a  tiny  image  of  the  gigantic 
elephant  on  my  retina  as  on  the  plate  of  a  camera- 
obscnra — this,  and  mucli  more,  is  wliat  he  sees  in  rmj  vis- 
ual feeling,  and  he  bids  me  see  it  also.  Grateful  for  the 
novel  instruction,  I  am  compelled  to  say  that  it  does 
not  alter  my  vision  of  the  elephant,  does  not  make  the 
fact  a  whit  clearer,  does  not  indeed  correspond  with  what 
I  feel.  It  is  outside  knowledge,  valuable,  as  all  knowl- 
edge is,  but  supplementary.  It  is  translation  into  another 
language.  And  when  I  come  to  examine  the  translation, 
I  find  it  very  imperfect.  I  ask  my  instructor :  Is  it  the 
tiny  image  on  my  retina  which  I  see,  and  not  the  big 
elephant  on  the  grass  ?  And  how  do  I  see  this  retinal 
image,  which  you  explain  to  be  upside  down  ?  —  how  is 
it  carried  from  my  retina  to  my  mind  ?  I  have  no  con- 
sciousness of  tiny  reversed  image,  none  of  my  retina, 
only  of  a  fact  of  feeling,  which  I  call  "seeing  an  ele- 
phant." The  camera-obscura  has  no  such  feeling — it 
reflects  the  image,  it  does  not  see  the  object.  Here  my 
instructor,  having  reached  the  limit  of  his  science,*  hands 
me  over  to  the  physiologist,  who  will  translate  the  fact 
for  me  in  terms  not  of  Geometry,  but  of  Anatomy  and 
Physiology.  The  laws  of  Dioptrics  cease  at  this  point : 
the  image  they  help  to  form  on  the  retina  is  ruthlessly 
dispersed,  and  all  its  beautiful  geometric  construction  is 
lost  in  a  neural  excitation,  wdiich  is  transmitted  through 
semifluid  channels  of  an  optic  tract  to  a  semifluid  gan- 
glion, whence  a  thrill  is  shot  through  the  whole  brain, 

*  "The  retinal  image  is  the  last  effect  known  of  the  action  of  objects 
on  us  ;  what  happens  beyond  the  retina  we  know  not ;  our  knowledge 
of  the  objective  process  has  at  present  here  its  limit."  —  Ewald  Hering, 
Beilrdge  zur  Physioloriie,  1862,  p.  166.  That  is  to  say,  we  have  a  defi- 
nite translation  of  the  process  in  geometric  terms  as  far  as  the  retina,  and 
thence  onwards  Geometry  fails  us,  and  Neurology  and  Psychology  are 
invoked. 


ANIMAL  AUTOMATISM.  393 

and  is  there  transformed  into  a  visual  sensation.  Again 
I  fancy  I  have  gained  novel  instruction  of  a  valuable 
kind ;  but  it  does  not  affect  my  original  experience  that 
I  am  enabled  to  translate  it  into  different  terms;  the 
less  so  because  I  cannot  help  the  conviction  that  the 
translation  is  imperfect,  leaving  out  the  essential  points. 
If  a  phrase  be  translated  for  me  into  French  or  German, 
I  gain  thereby  an  addition  to  my  linguistic  knowledge, 
but  the  experience  thus  variously  expressed  remains  un- 
affected. When  tlie  fact  is  expressed  in  geometrical  or 
physiological  terms,  the  inycMcal  i^occss  finds  no  ade- 
quate expression.  Neither  in  tlie  details,  nor  in  the 
totals,  do  I  recognize  any  of  the  quahties  of  my  state  of 
feeling  in  seeing  the  elephant.  I  do  not  see  the  geomet- 
rical process,  I  do  not  see  the  anatomical  mechanism,  I 
see  the  elephant,  and  am  conscious  only  of  that  feeling. 
You  may  consider  my  organism  geometrically  or  anatomi- 
cally, and  bring  it  thus  within  the  circle  of  objective 
knowledge ;  but  my  subjective  experience,  my  spiritual 
existence,  that  of  which  I  am  most  deeply  assured,  de- 
mands another  expression.  Nay  more,  on  closely  scru- 
tinizing your  objective  explanations,  it  is  evident  that  a 
psychical  process  is  im'pliecl  tliroughout  —  such  terms  as 
undulations,  refractions,  media,  lenses,  retina,  neural  ex- 
citation, overtly  refer,  indeed,  to  the  material  objective 
aspect  of  the  facts,  but  they  are  themselves  the  modes 
of  Feeling  by  which  the  facts  are  apprehended,  and  would 
not  exist  an  such  without  the  "  greeting  of  the  spirit." 

4G.  What,  then,  is  our  conclusion  ?  It  is,  that  to 
make  an  adequate  explanation  of  psychical  processes  by 
material  conditions  we  must  first  establisli  an  equiva- 
lence between  the  subjective  and  objective  aspects ;  and, 
having  taken  this  step,  we  must  complete  it  by  showing 
M'herein  the  difference  exists ;  having  established  this 
entity  and  diversity,  we  have  solved  the  problem. 
17* 


394  THE   niYSICAL   BASIS   OF   MIND. 

Let  us  attempt  this  solution.  When  I  speak  to  you, 
the  spoken  words  are  the  same  to  you  and  to  me.  You 
hear  what  I  hear,  you  apprehend  what  I  apprehend.  But 
there  were  muscular  movements  of  articulation  felt  by 
me  and  not  felt  by  you ;  to  feel  these  you  also  must 
articulate  the  words ;  but  so  long  as  you  merely  hear 
the  words,  there  is  a  difference  in  our  states  of  feeling. 
Some  of  my  movements  you  can  see,  others  you  can  im- 
agine ;  but  this  is  not  my  feeling  of  them,  it  is  your 
optical  equivalent  of  my  muscular  feeling.  On  a  similar 
assumption  of  equivalence,  a  neural  process  is  made  to 
stand  for  a  logical  process.  In  thinking  a  proposition, 
we  are  logically  grouping  verbal  symbols  representative 
of  sensible  experiences ;  and  this  is  a  quite  peculiar  state 
of  Consciousness,  wholly  unlike  what  would  arise  in  the 
mental  or  visual  contemplation  of  the  neural  grouping, 
which  is  its  physiological  equivalent.  But  this  diversity 
does  not  discredit  the  idea  of  their  identity;  and  al- 
though some  of  my  readers  will  protest  against  such  an 
idea,  and  will  affirm  that  the  logical  process  is 'not  a 
process  taking  place  in  the  organism  at  all,  but  in  a  spirit 
which  uses  the  organism  as  its  instrument,  I  must  be 
allowed  in  this  exposition  to  consider  the  identity  estab- 
lished, my  purpose  being  to  explain  the  diversity  neces- 
sarily accompanying  it.  Therefore,  I  say,  that  although 
a  logical  process  is  identical  with  a  neural  process,  it 
must  appear  differently  when  the  modes  of  apprehending 
it  are  different.  While  you  are  thinking  a  logical  propo- 
sition, grouping  your  verbal  symbols,  I,  who  mentally 
see  the  process,  am  grouping  a  totally  different  set  of 
symbols :  to  you  the  proposition  is  a  subjective  state,  i.  e. 
a  state  of  feeling,  not  an  object  of  feeling :  to  become  an 
object,  it  must  be  apprehended  by  objective  modes :  and 
this  it  can  become  to  you  as  to  me,  when  we  see  it  as  a 
process,  or  imagine  it  as  a  process.     But  obviously  your 


ANIMAL   AUTOMATISM.  395 

state  in  seeing  or  imagining  the  process  must  be  different 
from  your  state  when  the  process  itself  is  passing,  since 
the  modes  of  apprehension  are  so  different.  There  may 
be  every  ground  for  concluding  that  a  logical  process  has 
its  correlative  physical  process,  and  that  the  two  processes 
are  merely  two  aspects  of  one  event ;  but  because  we 
cannot  apprehend  the  one  aspect  as  we  apprehend  the 
other,  cannot  see  the  logical  sequence  as  we  see  the  physi- 
cal sequence,  this  difference  in  our  modes  of  apprehension 
compels  us  to  separate  the  two,  assigning  one  to  the  sub- 
jective, the  other  to  the  objective  class.  Between  the 
sensible  perception  of  an  object  and  the  reproduced  image 
of  the  object  there  is  chiefly  a  quantitative  difference  in 
the  physiological  and  psychological  processes :  the  image 
is  a  faint  sensation.  Yet  this  quantitative  difference 
brings  with  it  the  qualitative  distinction  which  is  indi- 
cated in  our  calling  the  one  a  sensation,  the  other  a 
thought.  The  consequence  has  been  that  while  all  phi- 
losophers have  admitted  the  sensation  to  be  —  at  least 
partly  —  a  process  in  the  bodily  organism,  the  majority 
have  maintained  that  the  thought  is  no  such  process  in 
the  organism,  but  has  its  seat  in  a  spirit  independent  of 
the  organism. 

47.  The  states  of  Feeling  which  are  associated  with 
other  states  characterized  as  objective  because  overtly 
referring  to  a  Not-Self,  we  group  under  the  head  of  Mat- 
ter: we  assign  material  conditions  as  their  antecedents. 
Whereas  states  of  Feeling  whicli  are  not  thus  associated 
we  group  under  the  head  of  Mind,  and  assign  internal 
conditions  as  their  antecedents.  Color  and  Taste  are 
very  different  states  of  Feeling,  yet  both  are  spontane- 
ously referred  to  external  causes,  because  they  are  asso- 
ciated with  visual  and  tactical  states ;  wliereas  ITuuger, 
Nausea,  Hope,  etc.,  have  no  such  associations,  and  their 
material  conditions  are  only  theoretically  assigned. 


396  THE  PHYSICAL  BASIS   OF   MIND. 

Our  intelligible  universe  is  constructed  out  of  the  ele- 
ments of  Feeling  according  to  certain  classifications,  the 
broadest  of  which  is  that  into  external  and  internal,  ob- 
ject and  subject.  The  abstractions  Matter  and  Mind 
once  formed  and  fixed  in  representative  symbols,  are 
easily  accredited  as  two  different  Eeals.  But  the  sepa- 
ration is  ideal,  and  is  really  a  distinction  of  Aspects. 
We  know  ourselves  as  Bbdy-Mind ;  we  do  not  know  our- 
selves as  Body  and  ]\Iind,  if  by  that  be  meant  two  coex- 
istent independent  Existents ;  and  the  illusion  by  which 
the  two  Aspects  appear  as  two  Eeals  may  be  made  intel- 
ligible by  the  analysis  of  any  ordinary  proposition.  For 
example,  when  we  say  "  this  fruit  is  sweet,"  wo,  express 
facts  of  Feeling  —  actual  or  anticipated  —  in  abstract 
terms.  The  concrete  facts  are  these  :  a  colored  feeling, 
a  solid  feeling,  a  sweet  feeling,  etc.,  have  been  associated 
together,  and  the  colored,  solid,  sweet  group  is  symbolized 
in  the  abstract  term  "  fruit."  But  the  color,  solidity,  and 
sweetness  are  also  abstract  terms,  representing  feelings 
associated  in  other  groups,  so  that  we  find  "  fruit "  w^hich 
has  no  "sweetness";  and  "sweetness"  in  other  things 
besides  "  fruits."  Having  thus  separated  ideally  the 
"sweetness"  from  the  "fruit"  —  wdiich  in  the  concrete 
sweet-fruit  is  not  permissible  —  we  easily  come  to  imagine 
a  real  distinction.  This  is  the  case  with  the  concrete  liv- 
insr  orcranism  when  we  cease  to  consider  it  in  its  concrete 
reality,  and  fix  our  attention  on  its  abstract  terms  — 
Body  and  Mind.  We  tlien  think  of  Body  apart  from 
Mind,  and  believe  in  tliem  as  two  Eeals,  though  neither 
exists  apart. 

There  is  no  state  of  consciousness  in  which  object  and 
subject  are  not  indissolubly  combined.  There  is  no  phys- 
ical process  which  is  not  indissolubly  bound  up  with 
the  psychical  modes  of  apprehending  it.  Every  idea  is 
either  an  image  or  a  symbol  —  it  has  therefore  objective 


ANDIAL  AUTOMATISM.  397 

reference,  a  material  aspect.  Every  object  is  a  synthesis 
of  feelings  —  it  has  therefore  subjective  reference,  a  ma- 
terial aspect.  Thus  while  all  the  evidence  points  to  the 
identity  of  Object  and  Subject,  there  is  ample  evidence 
for  the  logical  necessity  of  their  ideal  separation  as  As- 
pects. This  I  have  explained  as  a  case  of  the  general 
principle  which  determines  all  distinctions  —  namely,  the 
diversity  in  the  modes  of  production  of  the  products, 
which  —  subjectively  — is  diversity  in  the  modes  of  ap- 
prehending them.  The  optico-tactical  experiences  are 
markedly  different  from  the  other  experiences,  as  being 
more  directly  referred  to  the  Not-Self  wMch  resists ;  and 
because  these  lend  themselves  to  ideal  constructions  by 
means  of  images  and  symbols,  it  is  these  experiences  into 
which  we  translate  all  the  others  when  we  come  to  ex- 
plain them  and  assign  their  conditions.  For  —  and  this 
is  the  central  position  of  ovir  argument  —  all  interpre- 
tation consists  in  translating  one  set  of  feelings  in  the 
terms  of  another  set.  We  condense  sets  of  feelings  in 
abstract  symbols ;  to  understand  these  we  must  reduce 
them  to  their  concrete  significates.  They  are  signs ;  we 
must  show  what  they  are  signs  of 

Now  the  symbols  Object  and  Subject  are  the  most  ab- 
stract we  can  employ.  Because  they  are  universal,  they 
represent  what  cannot  in  reality  be  divorced.  We  can, 
indeed,  ideally  separate  ourselves  from  the  Cosmos ;  in 
the  same  way  we  can  ideally  separate  our  inner  Self  or 
Soul  from  our  outer  Self  or  Body ;  and  again  our  Soul 
from  its  sentient  states,  our  Body  from  its  physical 
changes.  But  not  so  in  reality.  The  separation  is  a 
logical  artifice,  and  a  logical  necessity  for  Science. 

The  necessity  will  be  obvious  to  any  one  who  reflects 
how  the  ideal  constructions  of  Science  demand  precision 
and  integrity  of  terms.  The  problem  of  Automatism 
brings  this  very  clearly  into  view.     The  question  is,  Can 


398  THE  niYSicAL  basis  of  mind. 

we  translate  all  psychological  phenomena  in  mechanical 
terms  ?  If  we  ca7i,  we  ought ;  because  these  terms  have 
the  immense  advantage  of  being  exact,  dealing  as  they  do 
with  quantitative  relations.  But  my  belief  is  that  we 
cannot  —  nay,  that  we  cannot  even  translate  them  all 
into  physiological  terms.  The  distinction  between  quan- 
titative and  qualitative  knowledge  (p.  354)  is  a  barrier 
against  the  mechanical  interpretation.  Physiology  is  a 
classificatory  science,  not  a  science  of  measurement.  Nor 
can  the  laws  of  Mind  be  deduced  from  physiological  pro- 
cesses, unless  supplemented  by  and  interpreted  by  psy- 
chical conditions  individual  and  social. 


ANIMAL  AUTOMATISM.  399 


CHAPTEE  IV. 

CONSCIOUSNESS   AND   UNCONSCIOUSNESS.* 

48.  Science  demands  precision  of  terms;  and  in  this 
sense  Condillac  was  justified  in  defining  it,  "  icne  langue 
Men  faiur  The  sciences  of  Measurement  are  exact  be- 
cause of  the  precision  of  their  terms,  and  are  powerful 
because  of  their  exactness.  The  sciences  of  Classification 
cannot  aspire  to  this  precision,  and  therefore,  although  ■ 
capable  of  attaining  to  a  fuller  knowledge  of  phenomena 
than  can  be  reached  by  their  rivals,  this  advantage  of  a 
wider  range  is  accompanied  by  the  disadvantage  of  a  less 
perfect  exposition  of  residts.  While  physicists  and  chem- 
ists have  only  to  settle  the  significance  of  the  facts 
observed,  biologists  and  social  theorists  have  over  and 
above  this  to  settle  the  significance  of  the  terms  they 
employ  in  expressing  the  facts  observed.  Hence  more 
than  half  their  disputes  are  at  bottom  verbal. 

This  is  markedly  the  case  in  the  question  of  Autom- 
atism. One  man  declares  that  animals  are  automata ; 
another  that  they  are  conscious  automata ;  and  while  it  is 
quite  possible  to  hold  these  views  and  not  practically  be 
in  disagreement  with  the  views  of  ordinary  men,  or  in- 
deed with  the  views  of  spiritualist  and  materialist  philoso- 
phers, we  can  never  be  sure  that  the  advocates  of  Autom- 
atism do  not  mean  wliat  they  are  generally  understood  to 
mean.  If  a  man  says  that  by  an  automaton  lie  does  not 
here  mean  a  machine,  such  as  a  steam-engine  or  a  watch, 

*  Compare  Problem  II.  Cliap.  IV. 


400  THE  PHYSICAL  BASIS   OF   MIND. 

but  a  vital  mechanism  whicli  lias  its  parts  so  adjusted 
that  its  actions  resemble  those  of  a  machine ;  and  if  he 
adds  that  this  automaton  is  also  conscious  of  some  of  its 
actions,  though  unconscious  of  others,  we  can  only  object 
to  his  using  terms  which  have  misleading  connotations. 
If  he  mean  by  "  conscious  automata,"  that  animals  are 
mechanisms  moved  on  "  purely  mechanical  principles," 
their  consciousness  having  notliing  whatever  to  do  with 
the  production  of  their  actions,  then  indeed  our  objection 
is  not  only  to  his  use  of  terms,  but  to  his  interpretation 
of  the  facts. 

49.  The  questions  of  fact  are  two :  Are  animal  mechan- 
isms rightfully  classed  beside  machines  ?  and.  Is  conscious- 
ness a  coefficient  in  the  actions  of  animal  mechanism  ? 
The  first  has  already  been  answered ;  the  second  demands 
a  preliminary  settlement  of  the  terms  "  conscious,"  "  un- 
conscious," "  voluntary,"  and  "  involuntary."  The  aim  of 
Physiology  is  to  ascertain  the  particular  combinations 
of  the  elementary  parts  involved  in  each  particular  func- 
tion —  in  a  word,  the  mechanism  of  organic  phenomena  ; 
and  the  modern  Eeflex  Theory  is  an  attempt  to  explain 
this  mechanism  on  purely  mechanical  principles,  without 
the  co-operation  of  other  principles,  especially  those  of 
Sensation  and  Volition.  It  is  greatly  aided  by  the  am- 
biguity of  current  terms.  We  are  accustomed  to  speak 
of  certain  actions  as  being  performed  unconsciously  or 
involuntarily.  We  are  also  accustomed  to  say  that  Con- 
sciousness is  necessary  to  transform  an  impression  into  a 
sensation,  and  that  Volition  is  the  equivalent  of  conscious 
effort.  "Wlien,  therefore,  unconscious  and  involuntary 
actions  are  recorded,  they  seem  to  be  actions  of  an  in- 
sentient mechanism.  The  Reflex  Theory  once  admitted, 
a  rigorous  logic  could  not  fail  to  extend  it  to  all  animal 
actions. 

50.  I  reject  the  Eeflex  Theory,  on  grounds  hereafter  to 


ANIMAL   AUTOMATISM.  401 

be  urged,  but  at  present  call  attention  to  the  great  ambi- 
guity in  the  terms  "  conscious  "  and  "  unconscious."  In 
one  sense  no  definition  of  Consciousness  can  be  satisfac- 
tory, since  it  designates  an  ultimate  fact,  which  cannot 
therefore  be  made  more  intelligible  than  it  is  already. 
In  another  sense  no  definition  is  needed,  since  every  one 
knows  what  is  meant  by  saying,  "  I  am  conscious  of  such 
a  change,  or  sucli  a  movement."  It  is  here  the  equivalent 
of  Feeling.  To  be  conscious  of  a  change,  is  to  feel  a 
change.  If  we  desire  to  express  it  in  physiological  terms, 
we  must  define  Consciousness  —  "a  function  of  the  organ- 
ism "  ;  and  tliis  definition  we  shall  find  eminently  useful, 
because  the  organism  being  a  vital  mechanism,  and  the 
integrity  of  that  mechanism  being  necessary  for  the  in- 
tegrity of  the  function,  while  every  variation  of  the  mechan- 
ism will  bring  a  corresponding  variatipn  of  the  function, 
we  shall  have  an  objective  guide  and  standard  in  our 
inquiries.  Organisms  greatly  differ  in  complexity,  yet 
because  they  also  agree  in  the  cardinal  conditions  of 
Vitality,  among  which  Sensibility  is  one,  we  conclude 
that  they  all  have  Feeling ;  but  the  Feeling  of  the  one 
will  differ  from  that  of  another,  according  to  the  com- 
plexity of  the  sentient  mechanism  in  each.  The  per- 
fection of  this  mechanism  lies  in  the  co-ordination  of  its 
parts,  and  the  consensus  of  its  sentient  activities  ;  any  dis- 
turbance of  that  consensus  must  cause  a  modification  in  the 
total  consciousness;  and  when  the  disturbance  is  profound 
the  modification  is  marked  by  such  terms  as  "  insanity," 
"loss  of  consciousness,"  "insensibility."  These  terms  do 
not  imply  that  tlie  sentient  organs  liave  lost  their  Sen- 
sibility, but  only  that  the  disturbed  meclianism  has  no 
longer  its  normal  consensus,  no  longer  jts  normal  state  of 
Consciousness.  Each  organ  is  active  in  its  own  way  so 
long  as  its  own  mechanism  is  preserved ;  but  the  united 
action  of  the  organs  having  been  disturbed,  their  resultant 


402  THE   PHYSICAL   BASIS   OF   MIND. 

function  has  been  altered.  Hence  in  a  fit  of  Epilepsy- 
there  is  a  complete  absence  of  some  normal  reactions, 
with  exaggeration  of  otliers.  In  a  state  of  Coma  there 
is  no  spontaneity  —  none  of  the  manifold  adaptations  of 
the  organism  to  fluctuating  excitations,  external  and  in- 
ternal, observable  in  the  normal  state.  The  organism 
still  manifests  Sensibility  —  but  this  is  so  unlike  the 
manifestations  when  its  mechanism  is  undisturbed  (and 
necessarily  so  since  the  Sensibility  varies  with  the  mechan- 
ism) that  it  is  no  longer  called  by  the  same  name.  In 
the  normal  organism  Sensibility  means  Feeling,  or  Con- 
sciousness ;  but  in  the  abnormal  organism  there  is  said  to 
be  a  "loss  of  Consciousness."  "VVliat  the  physiologist  or 
the  physician  means  by  the  phrase  "loss  of  Conscious- 
ness "  is  intelligible,  and  for  his  purposes  unobjectionable. 
He  observes  many  organic  processes  going  on  undisturbed 
—  the  unconscious  patient  breathes,  secretes,  moves  his 
limbs,  etc.  These  processes  are  referred  to  the  parts  of 
the  mechanism  which  are  not  disturbed ;  they  are  obvi- 
ously independent  of  that  adjustment  of  the  mechanism 
which  by  its  consensiis  has  the  special  resultant  named  Con- 
sciousness ;  he  therefore  concludes  that  these,  and  many 
other  organic  processes,  which  are  neither  accompanied 
nor  followed  by  discriminated  feelings,  are  the  direct  conse- 
quences of  the  stimulated  mechanism.  He  never  hesitates 
to  adopt  the  popular  language,  and  say,  ""We  sometimes 
act  unconsciously,  perceive  unconsciously,  and  even  think 
unconsciously,  all  by  the  simple  reflex  of  the  mechanism." 
Xow  observe  the  opening  for  error  in  this  language. 
The  actions  are  said  to  go  on  unconsciously,  and,  because 
unconsciously,  as  pure  reflexes,  which  are  then  assigned 
to  an  insentient  mechanism,  and  likened  to  the  actions 
of  machines.  But,  as  I  hope  hereafter  to  make  evident, 
the  reflex  mechanism  necessarily  involves  Sensibility; 
and  therefore  reflex  actions  may  be  unaccompanied  by 


ANIMAL  AUTOMATISM.  403 

Consciousness  —  in  one  meaning  of  that  term  —  without 
ceasing  to  be  sentient .  the  feelings  are  operative,  although 
not  discriminated.  On  the  other  hand,  there  is  another 
and  very  general  meaning  of  the  term  Consciousness, 
which  is  the  equivalent  of  Sentience. 

51.  In  discussing  Automatism,  or  the  Reflex  Theory,  it 
is  absolutely  necessary  that  we  should  first  settle  the 
meaning  we  assign  to  the  term  Consciousness*  The  lax- 
ity with  which  the  term  is  used  may  be  seen  in  the  enu- 
meration occupying  six  pages  of  Professor  Bain's  account 
of  the  various  meanings.  Psychology  is  often  said  to  be 
"the  science  of  the  facts  of  Consciousness";  and  the 
Brain  is  often  assigned  as  "  the  organ  of  Consciousness." 
Yet  there  are  many  mental  processes,  and  many  cerebral 
processes,  which  are  declared  to  be  unconscious.  Obvi- 
ously if  Consciousness  is  the  function  of  the  Brain,  there 
can  be  no  cerebral  activity  which  is  unconscious  ;  just  as 
there  can  be  no  activity  of  the  lungs  which  is  not  respira- 
tory. Usage  therefore  points  to  a  general  and  a  special 
sense  of  the  term.  The  general  usage  identifies  it  with 
Sensibility,  in  its  subjective  aspect  as  Sentience,  including 
all  psychical  states,  both  those  classed  under  Sensation, 
and  those  under  Thought.  These  states  are  the  "  facts  of 
consciousness  "  with  which  Psychology  is  occupied.  In 
the  special  usage  it  is  distinguished  from  all  other  psychi- 
cal states  by  a  peculiar  reflected  feeling  of  Attention, 
whereby  we  not  only  have  a  sensation,  but  also  fed  that 
we  have  it ;  we  not  only  think,  but  are  conscious  that  we 
are  thinking  ;  not  only  act,  but  are  conscious  of  what  we 
do  It  is  this  which  Kant  indicates  when  he  defines  it 
"  the  subjective  form  accompanying  all  our  conceptions 
(Begriffe)  "  ;  and  Jessen  Avhen  lie  defines  it  "  the  internal 
knowing  of  our  knowing,  an  in  itself  reilected  knowing."  * 

*  "Das  Bewusstwerden  ist  nichts  Anderes  als  cin  weiter  fortgeschrit- 
tenes  Eriimem  oder  Neuwerden  des  von  aussen  aufgenommenen  Wissens, 


404  THE   PHYSICAL   BASIS    OF   MIND. 

52.  We  shall  often  have  to  recur  to  this  general  and 
this  special  meaning,  both  of  which  are  too  hrmly  rooted 
for  any  successful  attempt  to  displace  them.  The  fact 
that  some  organic  processes  and  some  mental  processes 
take  place  now  consciously  and  now  unconsciously,  i.  e. 
now  witli  the  feeling  of  reflected  attention,  and  now  with 
no  such  feeling,  assuredly  demands  a  corresponding  ex- 
pression ;  ijor,  in  spite  of  inevitable  ambiguities,  is  there 
ground  for  regretting  that  the  expression  chosen  should 
be  only  an  extension  of  the  expression  already  adopted 
for  all  other  states  of  Sentience.  A  sentient  or  conscious 
state  can  only  be  a  state  of  the  sentient  organism,  itself 
the  unity  of  many  organs,  each  having  its  Sensibility. 
There  is  more  or  less  con.sensus,  but  there  is  no  introduc- 
tion of  a  new  agent  within  the  organism,  converting  what 
was  physical  impression  into  mental  reaction.  From  first 
to  last  there  has  been  nothing  but  neural  processes,  and 
combinations  of  such  processes  —  which,  viewed  subjec- 
tivel}',  are  sentient  processes.  Thus  the  gradations  of 
sensitive  reaction  are  Sentience,  Consentiencc,  and  Con- 
sciousness, whieli  are  represented  in  the  Logic  of  Feeling 
and  the  Lo^ic  of  Sii^ns.  The  familiar  term  Conscience 
will  then  represent  the  Logic  of  Conduct.  Thus  under- 
stood, we  may  say  that  a  man  sometimes  acts  uncon- 
sciously, or  thinks  unconsciously,  although  his  action  and 
thought  are  ruled  by  Consentience,  as  he  sometimes  acts 
and  thinks  unconscientiously,  although  he  is  not  without 
obedience  to  Conscience  on  other  occasions.  The  feeling 
which  determines  an  action  is  operative,  although  it  may 
not  be  discriminated  from  simultaneous  feelings.  When 
this  is  the  case,  we  say  the  feeling  is  unconscious;  but 
this  no  more  means  that  it  is  a  purely  physical  pro- 

ein  innerliches  Wissen  dieses  Wissens  oder  ein  in  sicli  reflectirtes  Wis- 
sen. ' ' — Jessf.x,  Versuch  einer  WissensclMftlichcn  Begriindung  der  Psycho- 
logic, 1855,  p.  477. 


ANIMAL  AUTOMATISM.  405 

cess  taking  place  outside  the  sphere  of  Sentience,  than  the 
immoral  conduct  of  a  man  would  be  said  to  be  mechani- 
cal, and  not  the  conduct  of  a  moral  agent.  There  is 
undoubtedly  a  marked  distinction  expressed  in  the  terms 
Consciousness  and  Unconsciousness,  but  it  is  not  that  of 
contrasts  such  as  Mental  and  Physical,  it  is  that  of  grades 
such  as  Light  and  Darkness.  Just  as  Darkness  is  a  posi- 
tive optical  sensation  very  different  from  mere  privation  — 
just  as  it  replaces  the  sensation  of  Light,  blends  with  it, 
struggles  with  it,  and  in  all  respects  differs  from  the  absence 
of  all  optical  sensibility  in  the  skin ;  so  Unconsciousness 
struggles  with,  blends  with,  and  replaces  Consciousness  in 
the  organism,  and  is  a  positive  state  of  the  sentient  organ- 
ism, not  to  be  confounded  with  a  mere  negation  of  Sen- 
tience ;  above  all,  not  to  be  relegated  to  merely  mechanical 
processes. 

52  a.  Eemember  tliat,  strictly  speaking.  Consciousness 
is  a  psycliological  not  a  physiological  term,  and  is  only 
used  in  Physiology  on  the  assumption  that  it  is  the  sub- 
jective equivalent  of  an  objective  process.  To  avoid  the 
equivoque  of  "  unconscious  sensation,"  we  may  substitute 
the  term  "  unconscious  neural  process  "  ;  and  as  all  neural 
processes  imply  Sensibility,  which  in  the  subjective  aspect 
is  Sentience,  we  say  that  Sentience  has  various  modes  and 
degrees  —  such  as  Perception,  Ideation,  Emotion,  Volition, 
which  may  be  conscious,  sub-conscious,  or  unconscious. 
When  Leibnitz  referred  to  the  fact  of  "obscure  ideas," 
and  modern  writers  expressed  this  fact  as  "unconscious 
cerebration,"  the  first  phrase  did  not  imply  a  process  that 
was  other  than  mental,  the  second  phrase  did  not  imply  a 
process  that  was  other  than  physiological :  botli  indicated 
a  mode  of  the  process  known  as  Consciousness  under  other 
modes.  There  are  different  neural  elements  grouped  in 
Ideation  and  Emotion  ;  there  are  different  neural  elements 
grouped  in  Consciousness,  Sub-consciousness,  and  Uncon- 


406  THE   PHYSICAL  BASIS   OF   MIND. 

sciousness;  but  one  tissue  with  one  property  is  active 
in  all. 

53.  The  nervous  organism  is  affected  as  a  whole  by  every 
affection  of  its  constituent  parts.  Every  excitation,  in- 
stead of  terminating  with  itself  —  as  is  the  case  in  most 
physical  processes  —  or  with  the  motor  impulse  it  excites, 
is  propagated  throughout  the  continuous  tissue,  and  thus 
sends  a  thrill  throughout  the  organism.  The  wave  of 
excitation  in  passing  onwards  beats  against  variously 
grouped  elements  —  temporary  and  permanent  centres  — 
disturbing  their  balance  more  or  less,  and  liberating  the 
energy  of  some,  increasing  the  tension  of  others,  neces- 
sarily affecting  all.  Those  groups  which  have  their  energy 
liberated  set  up  processes  that  are  either  discriminated  as 
sensations,  or  are  blended  with  the  general  stream,  accord- 
ing to  their  relative  energy  in  the  consensus.  Thus  the 
impulse  on  reaching  the  centres  for  the  heart,  lungs,  legs, 
and  tail  excites  the  innervation  of  these  organs ;  but  as 
these  are  only  parts  of  the  organism,  and  as  all  the  parts 
enter  the  consensus,  and  Consciousness  is  the  varying 
resultant  of  this  ever-varying  consensus,  the  thrill  which 
any  particular  stimulus  excites  will  be  unconscious,  sub- 
conscious, or  conscious,  in  proportion  to  the  extent  of  the 
irradiated  disturbance,  which  will  depend  on  the  statical 
conditions  of  the  centres  at  the  moment.  A  sound  sends 
a  thrill  which  excites  emotion,  causes  the  heart  to  beat 
faster,  the  muscles  to  quiver,  the  skin-glands  to  pour  forth 
their  secretion ;  yet  this  same  sound  heard  by  another 
man,  or  the  same  man  under  other  conditions,  physical  or 
historical,  merely  sends  a  faint  thrill,  just  vivid  enough 
to  detach  itself  as  a  sensation  from  the  other  simul- 
taneous excitations ;  and  the  same  sound  may  excite 
a  thrill  which  is  so  faint  and  fugitive  as  to  pass  un- 
consciously. Physiological  and  psychological  inductions 
assure  us  that  these  are  only  differences  of  degree.     The 


ANIMAL  AUTOMATISM.  407 

same  kind  of  physiological  effect  accompanies  the  con- 
scious and  unconscious  state.  Every  sensory  impres- 
sion, no  matter  whether  discriminated  or  not,  affects 
the  circulation  and  develops  heat.  The  blood-vessels  of 
the  part  impressed  expand,  vessels  elsewhere  contract  — 
a  change  in  the  blood  pressure  has  been  effected,  which 
of  course  implies  that  the  whole  organism  has  been 
affected.  Delicate  instruments  show  that  at  the  time 
a  sensation  is  produced  the  temperature  of  the  brain  is 
raised.  The  same  is  true  of  ideation.  Mosso  has  invented 
a  method  of  registering  the  effect  of  thought  on  the  cir- 
culation. He  finds  ideation  accompanied  by  a  contrac- 
tion of  the  peripheral  vessels  proportionate  to  the  degree 
of  intellectual  effort.  A  young  man  translating  Greek 
showed  greater  contraction  than  when  he  was  translating 
Latin.  During  sound  sleep  —  when  we  are  said  to  be 
unconscious  —  sudden  noises  always  cause  contraction 
of  the  peripheral  vessels.  Psychological  observation  as- 
sures us  that  the  conscious  and  unconscious  states  were 
both  consentient,  and  were  both  operative  in  the  same 
degree.  The  absorbed  thinker  threads  his  way  through 
crowded  streets,  and  is  sub-conscious  and  unconscious  of 
the  various  sights,  sounds,  touches,  and  muscular  move- 
ments which  make  up  so  large  a  portion  of  his  sentient 
excitation  at  the  time;  yet  he  deftly  avoids  obstacles,  hears 
the  sound  of  a  hurried  step  behind  him,  recognizes  an  in- 
teresting object  directly  it  presents  itself,  and  can  even 
recall  in  Memory  many  of  the  uninteresting  objects  wliicli 
he  passed  in  sub-conscious  and  unconscious  indifference. 

54.  On  all  grounds,  therefore,  we  must  say  that  be- 
tween conscious,  sub-conscious,  and  unconscious  states  the 
difference  is  only  of  degree  of  complication  in  the  neural 
processes,  which  by  relative  preponderance  in  the  con- 
sensus determine  a  relative  discrimination.  We  can  only 
discriminate  one  thrill  at  a  time ;  but  tlie  neural  excita- 


408  THE  niYsic.vL  basis  of  mind. 

tions  simultaneously  pressing  towards  a  discharge  are 
many;  and  the  conditions  which  determine  now  this,  and 
now  the  other  excitation  to  predominate  by  its  difi'erential 
pressure,  are  far  beyond  any  mechanical  estimate.  I 
mention  this  because  the  advocates  of  the  Eeflex  Theory 
maintain  that  the  neural  processes  are  the  same  whether 
a  sensation  be  produced  or  not ;  and  that  since  the  same 
actions  follow  the  external  stimulation  whether  sensation 
be  produced  or  not,  this  proves  the  actions  to  be  purely 
mechanical.  I  reply,  the  neural  processes  are  not  the 
same  tin-oughout  in  the  two  cases  —  otherwise  the  effects 
would  be  the  same.  You  might  as  well  say,  "  Since  the 
explosion  of  the  gun  is  the  same,  whether  shotted  or  not, 
a  blank  cartridge  will  kill " ;  but  if  you  tell  me  that  your 
gun  killed  the  bird,  I  declare  that  the  cartridge  was  not  a 
blank  one.  Whether  the  explosion  of  the  gun  also  pro- 
duced terror  in  one  bystander,  curiosity  in  a  second,  and 
attracted  no  notice  from  a  third,  will  be  altogetlier  another 
matter.  In  like  manner  the  sensory  impression  which 
determines  a  movement  may  or  may  not  be  accompanied 
or  followed  by  other  sentient  states ;  the  fact  of  such 
movement  is  evidence  of  its  sentient  antecedent ;  and  an 
external  stimulus  that  will  produce  this  neural  process, 
and  this  consequent  movement,  must  produce  a  feeling, 
although  not  necessarily  a  discriminated  sensation.  Now 
since,  for  discrimination,  other  neural  processes  must  co- 
operate, we  cannot  say  that  in  the  two  cases  all  the  neural 
processes  have  been  the  same  throughout ;  nor  because  of 
this  difference  can  we  say  that  the  process  of  the  undis- 
criminated sensation  is  a  mechanical,  not  a  sentient  process. 
In  the  next  problem  this  point  will  be  argued  more  fully. 
55.  The  need  of  recognizing  Consciousness  and  Con- 
sentience  as  degrees  of  energy  and  complexity  in  sen- 
tient states  is  apparent  when  we  consider  animal  phenom- 
ena.    Has  a  bee  consciousness  ?     Has  a  snail  volition  ? 


ANIMAL   AUTOMATISM.  409 

or  are  they  both  insentient  mechanisms  ?  All  inductions 
warrant  the  assertion  that  a  bee  has  thrills  propagated 
tln'oughout  its  organism  by  the  agency  of  its  nerves ;  and 
that  some  of  these  thrills  are  of  the  kind  called  sensa- 
tions —  even  discriminated  sensations.  Nevertheless  we 
may  reasonably  doubt  whether  the  bee  has  sentient  states 
resembling  otherwise  than  remotely  the  sensations,  emo- 
tions, and  thoughts  which  constitute  human  Conscious- 
ness, either  in  the  general  or  the  special  sense  of  that 
term.  The  bee  feels  and  reacts  on  feelings  ;  but  its  feel- 
ings cannot  closely  resemble  our  own,  because  the  condi- 
tions in  the  two  cases  are  different.  The  bee  may  even 
be  said  to  think  (in  so  far  as  Thought  means  logical  com- 
bination of  feelings),  for  it  appears  to  form  Judgments 
in  the  sphere  of  the  Logic  of  Feeling  —  to  potjtikov  ; 
althougli  incapable  of  the  Logic  of  Signs  —  to  SiavorjTtKov. 
We  should  therefore  say  the  bee  has  Consentience,  but 
not  Consciousness  —  unless  we  accept  Consciousness  in 
its  general  signification  as  the  equivalent  of  Sentience. 
The  organism  of  the  bee  differs  from  that  of  a  man,  as  a 
mud  hut  from  a  marble  palace.  But  since  underlying 
these  differences  there  are  fundamental  resemblances,  the 
functions  of  the  two  will  be  fundamentally  alike.  Both 
have  the  function  of  Sentience ;  as  mud  hut  and  palace 
have  both  the  office  of  sheltering. 

56.  The  question  of  Volition  will  occupy  us  in  the 
next  chapter.  Eestricting  ourselves  here  to  that  of 
Consciousness,  and  recalling  the  distinction  of  the  two 
meanings  of  tlie  term,  we  now  approach  the  question  of 
Unconsciousness.  Are  we  to  understand  this  term  as 
designating  a  purely  physical  state  in  contrast  to  tlie 
purely  mental  state  of  Consciousness ;  or  only  as  des- 
ignating a  difference  of  degree  ?  This  is  like  asking 
wliether  Light  and  Darkness  are  both  optical  feelings,  or 
one  an  optical  feeling  and  the  other  a  physical  process? 

VOL.   III.  18 


410  THE  niYsiCAL  basis  of  mind. 

On  the  Iveflex  Tlieory,  no  sooner  does  a  vital  and  mental 
process  pass  from  the  daylight  of  Consciousness,  or  twi- 
light of  Sub-consciousness,  into  the  darkness  of  Uncon- 
sciousness, than  the  whole  order  of  phenomena  is  abruptly 
changed,  they  cease  to  be  vital,  mental,  and  lapse  into 
physical,  mechanical  processes.  The  grounds  of  this  con- 
clusion are,  first,  the  unpsychological  assumption  that  the 
unconscious  state  is  out  of  the  sphere  of  Sentience ;  and 
secondly,  the  unphysiological  assumption  that  the  Brain 
is  the  only  portion  of  the  nervous  system  which  has  the 
property  of  Sensibility.  Eestate  the  conclusion  in  differ- 
ent terms  and  its  fallacy  emerges :  "  organic  processes 
suddenly  cease  to  be  organic,  and  become  purely  physical 
by  a  slight  change  in  their  relative  position  in  the  consen- 
sus ;  the  organic  process  which  was  a  conscious  sensation 
a  moment  ago,  when  its  energy  was  not  balanced  by 
some  other  process,  suddenly  falls  from  its  place  in  the 
gi'oup  of  organic  phenomena  —  sentient  phenomena  —  to 
sink  into  the  gTOup  of  inorganic  phenomena  now  that  its 
energy  is  balanced."  Consider  the  parallel  case  of  ]\Iotion 
and  Eest  in  the  objective  sphere.  They  are  two  functions 
of  the  co-operant  forces,  one  dynamic,  the  other  static ; 
although  markedly  distinguishable  as  functions,  M-e  know 
that  they  are  simply  tlie  co-operant  forces  now  unbalanced 
and  now  balanced ;  what  we  call  Eest  is^  also  a  product 
of  moving  forces,  each  of  which  is  operant,  and  will  issue 
in  a  definite  resultant  when  its  counter-force  is  removed. 
Motion  and  Eest  are  correlatives,  and  both  belong  to  the 
sphere  of  Kinetics.  In  like  manner  Consciousness  and 
Unconsciousness  are  correlatives,  both  belonging  to  the 
sphere  of  Sentience.*     Every  one  of  the  unconscious  pro- 

*  In  commoa'language  a  stone  or  a  tree  is  said  to  be  uncouscious  ;  but 
this  is  an  anthropomorphic  extension  of  the  term.  In  strictness  we 
should  no  more  speak  of  unconsciousness  outside  the  sphere  of  Sentience 
than  of  darkness  outside  the  sphere  of  Vision. 


AXIMAL  AUTOMATISM.  411 

cesses  is  operant,  changes  the  general  state  of  the  organ- 
ism, and  is  capable  of  at  once  issuing  in  a  discriminated 
sensation  when  the  force  which  balances  it  is  disturbed. 
I  was  unconscious  of  the  scratch  of  my  pen  in  writing 
the  last  sentence,  but  I  am  distinctly  conscious  of  every 
scratch  in  writing  this  one.  Then,  as  now,  the  scratching 
sound  sent  a  faint  thrill  through  my  organism,  but  its 
relative  intensity  was  too  faint  for  discrimination ;  now 
that  I  have  redistributed  the  co-operant  forces,  by  what  is 
called  an  act  of  Attention,  I  hear  distinctly  every  sound 
the  pen  produces. 

57.  The  inclusion  of  Sub-consciousness  within  the  sen- 
tient sphere  is  obvious ;  the  inclusion  of  Unconsciousness 
within  that  sphere  may  be  made  so,  when  we  consider  its 
modes  of  production,  and  compare  it  with  the  extra-sen- 
sible conception  of  molecules  and  atoms.  The  Matter 
which  is  sensible  as  masses,  may  be  resolved  into  mole- 
cules, which  lie  beyond  the  discrimination  of  sense ;  and 
these  again  into  atoms,  which  are  purely  ideal  concep- 
tions ;  but  because  molecules  are  proved,  and  atoms  are 
supposed,  to  have  material  properties,  and  to  conform  to 
sensible  canons  of  the  objective  world,  we  never  hesitate 
to  class  them  under  the  head  of  Matter ;  nor  do  we  im- 
agine that  in  passing  beyond  the  discrimination  of  Sense 
they  lose  their  objective  significance.  They  are  still  phys- 
ical, not  mental  facts.  So  with  Sentience :  we  may  trace 
it  through  infinite  gradations  from  Consciousness  to  Sub- 
consciousness, till  it  lades  away  in  Unconsciousness  ;  but 
from  first  to  last  the  processes  have  been  those  of  a  sen- 
tient organism ;  and  by  this  are  broadly  distinguished 
from  all  processes  in  anorganisms.  The  movement  of  a 
limb  has  quite  different  modes  of  production  from  the 
movement  of  a  wheel ;  and  among  its  m<ftles  must  be 
included  those  of  Sensibility,  a  peculiarly  vital  property. 
O.xidation  may  be  slow  or  rapid,  manifesting  itself  as  com- 


412  THE  PHYSICAL  BASIS   OF  MIND, 

bustion,  heat,  or  ilauie,  but  it  is  always  oxidation  — 
always  a  special  clieinical  phenomenon.  And  so  the  nen- 
ral  jn'ocess  of  Sentience,  whether  conscious,  sub-conscious, 
or  unconscious,  is  always  a  state  of  the  sentient  organism. 
If  a  material  process  does  not  change  its  character,  and 
become  spiritual,  on  passing  beyond  the  range  of  sensible 
appreciation,  why  should  a  psychical  process  become  ma- 
terial on  passing  beyond  the  range  of  discrimination  ?  If 
we  admit  molecules  as  physical  units,  sentient  tremors  are 
psychical  units.  The  extra-sensible  molecules  have  in- 
deed their  subjective  aspect,  and  only  enter  perception 
through  the  "  greeting  of  the  spirit."  The  sentient  tre- 
mors have  also  their  objective  aspect,  and  cannot  come 
into  existence  without  the  neural  tremors,  which  are  their 
physical  conditions. 

58.  It  is  only  by  holding  fast  to  such  a  conception  that 
we  can  escape  the  many  difficulties  and  contradictions 
presented  by  unconscious  phenomena,  and  explain  many 
physiological  and  psychological  processes.  Descartes  — 
followed  by  many  philosophers  —  identified  Consciousness 
with  Thought.  To  this  day  we  constantly  hear  that  to 
have  a  sensation,  and  to  be  conscious  of  it,  is  one  and  the 
same  state ;  which  is  only  admissible  on  the  understand- 
ing that  Consciousness  means  Sentience,  and  Sentience 
the  activity  of  the  nervous  system  viewed  subjectively. 
Leibnitz  pointed  out  that  we  have  many  psychical  states 
which  are  unconscious  states  —  to  have  an  idea  and  be 
conscious  of  it,  are,  he  said,  not  one  but  two  states. 
The  Consciousness  by  Descartes  erected  into  an  essential 
condition  of  Thought,  was  by  Leibnitz  reduced  to  an  ac- 
companiment which  not  only  may  be  absent,  but  in  the 
vast  majority  of  cases  is  absent.  The  teaching  of  most 
modern  psydhologists  is  that  Consciousness  forms  but  a 
small  item  in  the  total  of  psychical  processes.  Uncon- 
scious sensations,  ideas,  and  judgments  are  made  to  play 


ANIMAL  AUTOMATISM.  413 

a  great  part  in  their  explanations.  It  is  very  certain  that 
in  every  conscious  volition  —  every  act  that  is  so  charac- 
terized —  the  larger  part  of  it  is  quite  unconscious.  It  is 
equally  certain  that  in  every  perception  there  are  uncon- 
scious processes  of  reproduction  and  inference  —  there  is 
much  that  is  implicit,  some  of  which  cannot  be  made  ex- 
plicit —  a  "  middle  distance  "  of  sub-consciousness,  and  a 
"  background  "  of  unconsciousness.  But,  throughout,  the 
processes  are  those  of  Sentience. 

59.  Unconsciousness  is  by  some  writers  called  latent 
Consciousness.  Experiences  which  are  no  longer  mani- 
fested are  said  to  be  stored  up  in  ]\Iemory,  remaining  in 
the  Soul's  picture-gallery,  visible  directly  the  shutters  are 
opened.  We  are  not  conscious  of  these  feelings,  yet  they 
exist  as  latent  feelings,  and  become  salient  through  asso- 
ciation. As  a  metaphorical  expression  of  the  familiar 
facts  of  Memory  this  may  pass  ;  but  it  has  been  converted 
from  a  metaphor  into  an  hypothesis,  and  we  are  supposed 
to  have  feelings  and  ideas,  when  in  fact  we  have  nothing 
more  than  a  modified  disposition  of  the  organism  —  tem- 
porary or  ])ermanent  —  which  when  stimulated  will  re- 
spond in  tliis  modified  manner.  The  modification  of  the 
organism  when  permanent  becomes  hereditary  ;  and  its 
response  is  then  called  an  instinctive  or  automatic  action. 
And  as  actions  pass  by  degrees  from  conscious  and  vol- 
untary into  sub-conscious  and  sub-voluntary,  and  finally 
into  unconscious  and  involuntary,  we  call  them  volitional, 
secondarily  automatic,  and  automatic.  If  any  one  likes 
to  say  the  last  are  due  to  latent  consciousness,  I  sliall  not 
object.  I  only  point  to  the  fact  that  the  differences  here 
specified  are  simply  differences  of  degree  —  all  the  actions 
are  those  of  the  sentient  organism. 

60.  Picture  to  your.self  this  sentient  organism  inces- 
santly stimulated  from  without  and  from  within,  and 
adjusting  itself  in  response  to  such  stimulations.      In  the 


414  THE   riIYSIC.\I.  BASIS   OF  MIND. 

blending  of  stimulations,  modifying  and  arresting  eacli 
other,  there  is  a  fluctuating  "composition  of  forces,"  with 
ever-varying  resultants.  Besides  the  stream  of  direct 
stimulations,  there  is  a  wider  stream  of  indirect  or  repro- 
duced stimulations.  Together  with  the  present  sensation 
there  is  always  a  more  or  less  complex  group  of  revived 
sensations,  the  one  group  of  neural  tremors  being  organi- 
cally stimulated  by  the  other.  An  isolated  excitation  is 
impossible  in  a  continuous  nervous  tissue ;  an  isolated 
feeling  is  impossible  in  the  consensus  or  unity  of  the 
sentient  organism.  The  term  Soul  is  the  personification 
of  this  complex  of  present  and  revived  feelings,  and  is 
the  substratum  of  Consciousness  (in  the  general  sense), 
all  the  particular  feelings  being  its  states.  To  repeat  an 
illustration  used  in  my  first  volume,  we  may  compare 
Consciousness  to  a  mass  of  stationary  waves.  If  the  sur- 
face of  a  lake  be  set  in  motion  each  wave  diffuses  itself 
over  the  whole  surface,  and  finally  reaches  the  shores, 
whence  it  is  reflected  back  towards  the  centre  of  the  lake. 
This  reflected  wave  is  met  by  the  fresh  incoming  waves, 
there  is  a  blending  of  the  waves,  and  their  product  is  a 
pattern  on  the  surface.  This  pattern  of  stationary  waves 
is  a  fluctuating  pattern,  because  of  the  incessant  arrival 
of  fresh  waves,  incoming  and  reflected.  "V\Tienever  a  fresh 
stream  enters  the  lake  (i.  e.  a  new  sensation  is  excited 
from  without),  its  waves  will  at  first  pass  over  the  pat- 
tern, neither  disturbing  it  nor  being  disturbed  by  it ;  but 
after  reaching  the  shore  the  waves  will  be  reflected  back 
towards  the  centre,  and  there  will  more  or  less  modify 
the  pattern. 


ANIMAL  AUTOMATISM.  415 


CHAPTEE    V. 

VOLUNTARY   AND   INVOLUNTARY   ACTIONS. 

61.  Much  of  what  has  been  said  in  the  preceding 
chapter  respecting  the  passive  side  of  the  organism  is 
equally  applicable  to  the  active  side.  Our  actions  are 
classed  as  voluntary  and  involuntary  mainly  in  reference 
to  their  being  consciously  or  unconsciously  j^erformed ; 
but  not  wholly  so,  for  there  are  many  involuntary  actions 
of  which  we  are  distinctly  conscious,  and  many  voluntary 
actions  of  which  we  are  at  times  sub-conscious  and  un- 
conscious. I  do  not  propose  here  to  open  the  long  and 
arduous  discussion  as  to  what  constitutes  Volition,  my 
present  purpose  being  simply  that  of  fixing  the  meaning 
of  terms,  so  that  the  question  of  Automatism  may  not  be 
complicated  by  their  ambiguities.  "  Voluntary  "  and  "  in- 
voluntary "  are,  like  "  conscious  "  and  "  unconscious,"  cor- 
relative terms ;  but  commonly,  instead  of  being  under- 
stood as  indicating  differences  of  degree  in  phenomena 
of  the  same  order,  they  are  supposed  to  indicate  differ- 
ences of  kind  —  a  new  agent,  the  Will,  being  understood 
in  the  one  case  to  direct  the  Mechanism  whicli  suffices 
without  direction  in  the  other. 

02.  This  interpretation  is  imphysiological  and  unpsy- 
chological,  since  it  overlooks  the  fact  that  both  voluntary 
and  involuntary  actions  belong  to  the  same  order  of  phe- 
nomena, i.  e.  those  of  the  sentient  organism.  Botli  in- 
volve the  same  efficient  cause,  i.  e.  co-operant  conditions. 
We  draw  a  line  of  demarcation  between  the  two  aljstrac- 


416         THE  PHYSICAL  BASIS  OF  MIND, 

tions  —  as  between  all  abstractions  —  but  the  concrete 
l)rocesses  they  symbolize  liave  uo  such  demarcation. 
Just  as  the  thought  which  at  one  moment  passes  un- 
consciously, at  another  consciously,  is  in  itself  the  same 
thought,  and  the  same  neural  process;  so  the  action  which 
at  one  moment  is  voluntary,  and  at  another  involuntary, 
is  itself  the  same  action,  performed  by  the  same  mechan- 
ism. The  incitation  which  precedes,  and  the  feeling 
which  accompanies  the  action,  belong  to  the  accessory 
mechanisms,  and  may  be  replaced  by  other  incitations 
and  other  feelings ;  as  the  fall  of  an  apple  is  the  same 
event,  involving  the  same  conditions,  i.  e.  efficient  cause, 
whether  the  occasional  cause  be  a  gust  of  wind  or  the 
gardener's  scissors,  and  whether  the  fall  be  seen  and 
heard  or  not.  I  may  utter  words  intentionally  and  con- 
sciously, and  I  may  utter  the  same  words  automaticall}', 
unconsciously ;  I  may  wink  voluntarily,  and  wink  in- 
voluntarily. There  are  terms  to  express  these  differ- 
ences ;  but  they  do  not  express  a  difference  in  the  efficient 
agencies. 

63.  Many  writers  seem  to  think  that  the  involuntary 
actions  belong  to  the  physical  mechanical  order,  because 
they  are  not  stimulated  by  cerebral  incitations,  and  can- 
not be  regulated  or  controlled  by  such  incitations  —  or  as 
the  psychologists  would  say,  because  Consciousness  in 
the  form  of  Will  is  no  agent  prompting  and  regulating 
such  actions.  But  I  think  this  untenable.  The  actions 
cannot  belong  to  the  mechanical  order  so  long  as  they  are 
the  actions  of  a  vital  mechanism,  and  so  long  as  we  admit 
the  broad  distinction  beween  organisms  and  anorganisms. 
Whether  they  have  the  special  character  of  Consciousness 
or  not,  they  have  the  general  character  of  sentient  actions, 
being  those  of  a  sentient  mechanism.  And  this  becomes 
the  more  e\ddent  when  we  consider  the  gradations  of  the 
phenomena.     Many,  if  not  all,  of  those  actions  w-hich  are 


ANIMAL   AUTOMATISM.  417 

classed  under  the  involuntary  were  originally  of  the  vol- 
untary class —  either  in  the  individual  or  his  ancestors ; 
but  having  l)ecoine  permanently  organized  dispositions  — 
the  pathways  of  stimulation  and  reaction  having  been 
definitely  established  —  they  have  lost  that  volitional  ele- 
ment (of  hesitation  and  choice)  which  implies  regulation 
and  control.  But  even  here  a  slight  change  in  the  habit- 
ual conditions  will  introduce  a  disturbance  in  the  process 
which  may  awaken  Consciousness,  and  the  sense  of  effort, 
sometimes  even  causing  control.  An  instinctive  or  an 
automatic  action  may  be  thus  changed,  or  arrested.  Take 
as  an  example  one  of  the  unequivocally  automatic  actions, 
that  of  Breathing.  It  is  called  automatic  because,  like 
the  actions  of  an  automaton,  it  is  performed  by  a  defi- 
nitely constructed  mechanism,  always  working  in  the 
same  way  when  stimulated  and  left  to  itself.  There  must 
of  course  be  a  sense  of  effort  in  every  impulse  which  has 
resistance  to  overcome,  organs  to  be  moved ;  but  the 
mechanism  of  Breathing  is  so  delicately  adjusted,  that 
the  sense  of  effort  is  reduced  to  a  minimum,  and  we  are 
imconscious  of  it,  or  sub-conscious  of  it.  Nevertheless, 
without  altering  the  rate  or  amplitude  of  the  inspirations 
and  expirations,  we  become  distinctly  conscious  of  them, 
and,  moreover,  within  certain  limits  we  can  control  them, 
so  that  the  Breathing  passes  from  the  involuntary  to  the 
voluntary  class. 

64.  Pass  on  to  other  examples.  What  action  can  be 
more  involuntary  than  the  rhythmic  movements  of  the 
heart  and  the  contractions  of  the  iris  ?  Compared  with 
the  actions  of  the  tongue  or  limbs,  these  seem  riveted  by 
an  iron  necessity,  freed  from  all  consciousness  and  con- 
trol. Yet  the  movements  of  the  heart  are  not  only  stim- 
ulated by  sensations  and  thoughts,  they  are  also  ca])alile 
of  being  felt;  and  tlie  movements  both  of  heart  and  iris 
are  not  wholly  removed  from  our  control.     That  we  do 

18*  AA 


418  THE  riiYSicAL  basis  of  mind. 

not  habitually  control  (that  is,  interfere  with)  the  action 
of  the  heart,  the  contraction  of  the  iris,  or  the  activity  of 
a  sland,  is  true ;  it  is  on  this  account  that  such  actions 
are  called  involuntary ;  they  obey  the  immediate  stimu- 
lus. But  it  is  an  error  to  assert  that  these  actions  cannot 
be  controlled,  that  they  are  altogether  beyond  the  inter- 
ference of  other  centres,  and  cannot  by  any  effort  of  ours 
be  modified.  It  is  an  error  to  suppose  these  actions  are 
essentially  distinguished  from  the  voluntary  movement 
of  tlie  hands.  We  have  acquired  a  power  of  definite 
direction  in  the  movements  of  the  hands,  which  renders 
them  obedient  to  our  will ;  but  this  acquisition  has  been 
of  slow  laborious  growth.  If  we  were  asked  to  use  our 
toes  as  we  use  our  fingers  —  to  grasp,  paint,  sew,  or  write 
with  them,  we  should  find  it  not  less  impossible  to  con- 
trol the  movements  of  the  toes  in  these  directions,  than 
to  contract  the  iris,  or  cause  a  burst  of  perspiration  to 
break  forth.  Certain  movements  of  the  toes  are  possible 
to  us ;  but  unless  the  loss  of  our  fingers '  has  made,  it 
necessary  that  we  should  use  our  toes  in  complicated 
and  slowly  acquired  movements,  we  can  do  no  more  with 
them  than  the  young  infant  can  do  with  his  fingers.  Yet 
men  and  women  have  written,  sewed,  and  painted  with 
their  toes.  All  that  is  requisite  is  that  certain  links 
should  be  established  between  sensations  and  movements ; 
by  continual  j)ractice  these  links  arc  established  ;  and 
what  is  impossible  to  the  majority  of  men,  becomes  easy 
to  the  individual  who  lias  acquired  this  power.  This 
same  power  can  be  acquired  over  what  are  called  the 
organic  actions ;  nevertlieless  the  habitual  needs  of  life 
do  not  tend  towards  such  acquisition,  and  without  some 
strong  current  setting  in  that  direction,  or  some  pecul- 
iarity of  organization  rendering  it  easy,  it  is  never  ac- 
quired. In  ordinary  circumstances  the  number  of  those 
who  can  w^ite  with  their  toes  is  extremely  rare,  the  ur- 


ANIMAL  AUTOMATISM.  419 

gent  necessity  which  would  create  such  a  power  being 
rare ;  and  rare  also  are  the  examples  of  those  who  have 
any  control  over  the  movement  of  the  iris,  or  the  action 
of  a  gland  ;  but  both  rarities  exist. 

It  would  be  difficult  to  choose  a  more  striking  example 
of  reflex  action  than  the  contraction  of  the  iris  of  the  eye 
under  the  stimulus  of  light ;  *  and  to  ordinary  men,  hav- 
ing no  link  established  which  would  guide  them,  it  is 
utterly  impossible  to  close  the  iris  by  any  effort.  It 
woukl  be  not  less  impossible  to  the  hungry  chikl  to  get 
on  the  chair  and  reach  the  food  on  the  table,  until  that 
child  had  learned  how  to  do  so.  Yet  there  are  men  who 
liave  learned  how  to  contract  the  iris.  The  celebrated 
Fontana  had  this  power;  which  is  possessed  also  by  a 
medical  man  now  living  at  Kilmarnock  —  Dr.  Paxton  — 
a  fact  authenticated  by  no  less  a  person  than  Dr.  Allen 
Thomson.!  Dr.  Paxton  can  contract  or  expand  the  iris 
at  will,  without  changing  the  position  of  his  eye,  and 
without  an  effort  of  adaptation  to  distance. 

To  move  the  ears  is  impossible  to  most  men.  Yet 
some  do  it  with  ease,  and  all  could  learn  to  do  it.  Some 
men  have  learned  to  "ruminate"  their  food;  others  to 
vomit  with  ease ;  and  some  are  said  to  have  the  power  of 
perspiring  at  will.  %  Now,  if  once  we  recognize  a  link  of 
sensation  and  motion,  we  recognize  a  possible  source 
of  control ;  and  if  the  daily  needs  of  life  were  such  that 
to  fulfil  some  purpose  the  action  of  the  heart  required 
control,  we  should  learn  to  control  it.  Some  men  have, 
without  such  needs,  learned  how  to  control  it.  The 
eminent  physiologist,  E.  F.  Weber  of  Leipzig,  found  that 

*  The  contraction  may  be  effected  in  tlie  ej'e  out  of  the  organism. 
See  p.  229.     It  is  then  no  reflex. 

t  Glasgov)  Medical  Journal,  1857,  p.  451.  See  also  further  on,  note 
to  p.  426. 

X  Mayer,  Die  Elementar organisation  ties  Scclcnorgans,  p.  12,  is  the 
authority  for  the  last  statement. 


420  tiil:  physical  basis  of  mind. 

he  could  completely  check  the  beating  of  his  heart.  By 
suspending  his  breath  and  violently  contracting  his  chest, 
he  could  retard  the  pulsations ;  and  after  three  or  five 
beats,  unaccompanied  by  any  of  the  usual  sounds,  it  was 
completely  still.  On  one  occasion  he  carried  the  experi- 
ment too  far,  and  fell  into  a  syncope.  Cheyne,  in  the 
last  century,  recorded  the  case  of  a  patient  of  his  own 
who  could  at  will  suspend  the  beating  of  liis  pulse,  and 
always  fainted  when  he  did  so. 

65.  It  thus  appears  that  even  the  actions  which  most 
distinctly  bear  the  character  recognized  as  involuntary 
—  uncontrollable  —  are  only  so  because  the  ordinary 
processes  of  life  furnish  no  necessity  for  their  control. 
We  do  not  learn  to  control  them,  though  we  could  do 
so,  to  some  extent ;  nor  do  we  learn  to  control  the  mo- 
tions of  our  ears,  although  we  could  do  so.  And  while 
it  appears  that  the  involuntary  actions  can  become  vol- 
untary, it  is  familiar  to  all  that  the  voluntary  actions 
tend,  by  constant  repetition,  to  become  involuntary. 
Thus  involuntary  actions,  under  certain  limitations,  may 
be  controlled ;  on  the  other  hand,  the  voluntary  are  in- 
capable of  being  controlled  under  the  urgency  of  direct 
stimulation.     Both  are  reflexes. 

Inasmuch  as  almost  all  actions  are  the  products  of 
stimulated  nerve-centres,  it  is  obvious  that  these  actions 
are  reflex  —  reflected  from  those  centres.  It  matters  not 
whether  I  wink  because  a  sensation  of  dryness,  or  be- 
cause an  idea  of  danger,  causes  the  eyelid  to  close :  the 
act  is  equally  reflex.  The  nerve-centre  which  supplies 
the  eyelid  with  its  nerve  has  been  stimulated ;  the  stim- 
uli may  be  various,  the  act  is  uniform.  At  one  time  the 
stimulus  is  a  sensation  of  dryness,  at  another  an  idea 
of  danger,  at  another  the  idea  of  communicating  by 
means  of  a  wink  with  some  one  present ;  in  each  case 
the  stimulus  is  reflected  in  a  muscular  contraction.     Sen- 


ANIMAL   AUTOMATISM,  421 

sations  excite  other  sensations ;  ideas  excite  other  ideas ; 
and  one  of  these  ideas  may  issue  in  an  action  of  control. 
But  the  restraining  power  is  limited,  and  cannot  resist  a 
certain  degree  of  urgency  in  the  original  stimulus.  I 
can,  for  a  time,  restrain  the  act  of  winking,  in  spite  of  the 
sensation  of  dryness ;  but  the  reflex  which  sets  going  this 
restraining  action  will  only  last  a  few  seconds ;  after 
which,  the  urgency  of  the  external  stimulus  is  stronger 
than  that  of  the  reflex  feeling  —  the  sensation  of  dryness 
is  more  imperious  than  the  idea  of  resistance  —  and  the 
eyelid  drops. 

If  a  knife  be  brought  near  the  arm  of  a  man  who  has 
little  confidence  in  the  friendly  intentions  of  him  that 
holds  it,  he  shrinks,  and  the  shrinking  is  "  involuntary," 
i.  e.  in  spite  of  his  will.  Let  him  have  confidence,  and 
he  does  not  shrink,  even  when  the  knife  touches  his  skin. 
The  idea  of  danger  is  not  excited  in  the  second  case,  or 
if  excited,  is  at  once  banished  by  another  idea.  Yet  this 
very  man,  who  can  tlius  repress  the  involuntary  sln^ink- 
ing  when  the  knife  approaches  his  arm,  cannot  repress 
the  involuntary  winking  when  the  same  friend  approaches 
a  finger  to  his  eye.  In  vain  he  prepares  himself  to  resist 
that  reflex  action ;  in  vain  ho  resolves  to  resist  the  im- 
pulse ;  no  sooner  does  the  finger  approach,  than  down 
flashes  the  eyelid.  Many  men,  and  most  women,  would 
])e  equally  unable  to  resist  shrinking  on  the  approach  of 
a  knife :  the  association  of  the  idea  of  danger  with  the 
knife  would  bear  down  any  previous  resolution  not  to 
shrink.  It  is  from  this  cause  that  timorous  women  trem- 
ble at  the  approach  of  firearms.  An  association  is  estab- 
lished in  their  minds  whicli  no  idea  is  powerful  enough 
to  loosen.  You  may  assure  them  the  gun  is  not  loaded ; 
"  fhat  makes  very 'little  difference,"  said  a  naive  old  lady 
to  a  friend  of  mine.  They  tremble,  as  the  child  trembles 
when  lie  sees  you  put  on  the  mask.     Tliese  illustrations 


422  THE   PHYSICAL  BASIS   OF  MIND. 

show  that  the  urgency  of  any  one  idea  may,  like  the  ur- 
gency of  a  sensation,  bear  down  the  resistance  offered  by 
some  other  idea ;  as  the  previous  illustrations  showed 
that  an  idea  could  restrain  or  control  the  action  which  a 
sensation  or  idea  would  otherwise  have  produced.  Ac-, 
cording  to  the  doctrines  current,  the  Will  is  said  to  be 
operative  when  an  idea  determines  an  action  ;  and  yet  all 
would  agree  that  the  winking  which  was  involuntary 
when  the  idea  of  danger  determined  it,  was  voluntary 
when  the  idea  of  communicating  with  an  accomplice  in 
some  mystification  determined  it. 

66.  There  is  no  real  and  essential  distinction  between 
voluntary  and  involuntary  actions.  They  all  spring  from 
Sensibility.  They  are  all  determined  by  feeling.  It  is 
convenient,  for  common  purposes,  to  designate  some  ac- 
tions as  voluntary  ;  but  this  is  merely  a  convenience  ;  no 
psychological  nor  physiological  insight  is  gained  by  it ;  an 
analysis  of  the  process  discloses  no  element  in  a  volun- 
tary action  which  is  not  to  be  found  in  an  involuntary 
action  —  except  in  the  origin  or  degree  of  stimulation. 
In  ordinary  language  it  is  convenient  to  mark  a  distinc- 
tion between  my  raising  my  arm  because  I  will  to  raise  it 
for  some  definite  purpose,  and  my  raising  it  because  a  bee 
has  stung  me ;  it  is  convenient  to  say,  "  I  %oill  to  write 
this  letter,"  and  "  this  letter  is  written  against  my  will  — 
I  have  no  will  in  the  matter."  But  Science  is  more  exact- 
ing when  it  aims  at  being  exact ;  and  the  philosopher, 
analyzing  these  complex  actions,  will  find  that  in  eacli 
case  certain  muscular  groups  have  been  set  in  action  by 
different  sensational  or  ideational  stimuli.  The  action 
itself  is  that  of  a  neuro-muscular  meclianism,  which 
mechanism  works  in  the  same  way,  whatever  be  the  source 
of  the  original  impulse.  The  stimulation  may  be  incited 
directly  from  the  periphery,  or  indirectly  from  a  remote 
centre ;  and  the  action  may  be  arrested  by  a  peripheral  or 


ANIMAL  AUTOMATISM.  423 

central  stimulation :  the  reflex  which  ordinarily  follows 
the  excitation  of  a  sensory  nerve  will  be  modified,  or 
arrested,  if  some  other  nerve  be  at  the  same  time  stimu- 
lated.    (See  Law  of  Arrest,  Proh.  II.  §  190.) 

67.  All  actions  are  reflex,  all  are  the  operations  of  a 
mechanism,  all  are  sentient,  because  the  mechanism  has 
Sensibility  as  its  vital  property.  In  thus  preserving  the 
integrity  of  the  order  of  vital  phenomena,  and  keeping 
them  classified  apart  from  physical  and  chemical  phenom- 
ena, we  by  no  means  set  aside  the  useful  distinctions  ex- 
pressed in  the  terms  voluntary  and  involuntary  ;  any  more 
than  we  set  aside  the  distinction  of  vertebrate  and  inver- 
tebrate w^hen  both  are  classed  under  Animal,  and  sepa- 
rated from  Plant,  or  Planet. 

The  mechanisms  of  the  special  Senses  respond  in  spe- 
cial reactions ;  the  mechanisms  of  special  actions  have 
also  their  several  responses.  The  tail  responds  to  stimu- 
lation with  lateral  movements,  the  chest  with  inspiration 
and  expiration,  and  so  on.  These  responses  are  called 
automatic,  and  have  this  in  common  with  the  actions  of 
automata  that  they  are  uniform,  and  do  not  need  the 
co-operation  of  Consciousness,  though  they  do  need  the 
operation  of  Sensibility,  and  are  thereby  distinguished  from 
the  actions  of  automata.  The  facial  muscles,  and  the 
limbs,  also  respond  to  stimulation  in  uniform  ways,  but 
owing  to  the  varieties  of  stimulation  the  actions  are  more 
variable,  and  have  more  the  character  of  volitional  move- 
ments. With  this  greater  freedom  of  possible  action 
comes  tlie  eminently  mental  character  of  choice.  In  the 
cerebral  rehearsal  of  an  act  not  yet  performed  —  its  men- 
tal prevision  —  as  when  we  intend  to  do  something,  yet 
for  the  moment  arrest  the  act,  so  that  there  is  only  a  nas- 
cent excitation  of  the  motor  process,  there  is  a  peculiar 
state  of  Consciousness  expressive  of  this  state  of  tlie 
mechanism  :  we  call  tlie  prevision  a  motive — and  it  be- 


424  THE   PHYSICAL   BASIS   OF   MIND. 

comes  a  motor  when  the  intention  is  realized,  the  nascent 
excitation  becomes  an  unchecked  inii)ulse.  The  abstract 
of  all  motives  we  call  Will.  A  motive  is  a  volition  in 
the  sphere  of  the  Intellect.  In  the  sphere  of  Emotion  it 
is  a  motor.  Hence  we  never  speak  of  the  Will  of  a  mol- 
lusc, or  the  motives  of  an  insect,  only  of  their  sensations 
and  motors.  Yet  it  is  obvious  that  the  reflex  in  operation 
when  a  snail  shrinks  at  the  approach  of  an  object  is  essen- 
tially similar  to  the  reflex  in  operation  when  the  baby 
shrinks,  and  this  again  is  still  more  similar  to  that  in 
operation  when  the  boy  shrinks  :  the  boy  has  the  idea  of 
danger,  M'hich  neither  baby  nor  snail  can  have ;  the  idea 
is  a  motive,  which  can  be  controlled  by  another  idea ; 
the  baby  and  the  snail  can  have  no  such  motive,  no  such 
control  —  are  they  therefore  automata  ? 

68.  If  I  see  that  a  donkey  has  wandered  into  my  gar- 
den, the  motive  which  determines  me  to  take  a  stick  and 
with  it  drive  the  donkey  away  is  a  cerebral  rehearsal  of 
the  effects  which  will  follow  my  act.  The  sight  of  the 
donkey  has  roused  disagreeable  feelings,  and  these  suggest 
possible  means  of  alleviation  ;  out  of  these  possibilities 
—  reproductions  of  former  experiences  —  I  choose  one. 
But  if  I  seize  the  stick  with  which  some  one  is  threaten- 
ing me,  I  do  not  pause  to  choose,  I  snatch  automatically 
without  hesitation.  Yet  this  unreflecting  automatic  act 
is  itself  as  truly  volitional  as  my  seizing  the  stick  to  drive 
away  the  donkey  —  it  is  the  motor  which  has  been  organ- 
ized in  me  by  previous  experiences  —  it  is  the  conse- 
quence of  an  emotion,  not  of  a  deliberation ;  and  it  has 
not  been  determined  by  any  clear  prevision  of  conse- 
quences. Feeling  inspires,  and  feeling  guides  my  move- 
ments, so  that  if  my  snatch  has  missed  the  stick,  I  snatch 
again,  or  duck  under.  This  is  the  kind  of  Volition  we 
ascribe  to  animals.  It  is  a  great  part  of  our  own.  By 
insensible  degrees,  acts  which  originally  were  prompted 


ANIMAL  AUTOMATISM.  425 

by  motives  sink  into  the  automatic  class  prompted  by- 
motors.  When  an  angry  man  snatches  up  a  knife,  doffs 
bystanders  aside,  and  rushes  on  liis  enemy  to  stab  him,  he 
does  not  distinctly  prefigure  the  final  result,  he  only  obeys 
each  motor,  and  is  conscious  of  each  step ;  but  had  he 
planned  the  murder  he  would  have  foreseen  the  end,  and 
this  prevision  would  have  been  the  motive.  The  angry 
man  is  struck  witli  liorror  at  the  sight  of  the  bleeding 
corpse,  and  passionately  declares  he  did  not  mean  to  kill. 
Nor  did  he  will  the  consequences  of  his  act,  yet  he  cer- 
tainly willed  each  separate  step  —  he  recognized  the  knife, 
saw  the  bystanders,  knew  they  would  interfere  with  him, 
willed  to  push  them  aside.  He  may  be  right  in  declaring 
that  the  act  was  involuntary ;  but  assuredly  it  was  not 
purely  mechanical. 

G9.  Again,  we  are  not  conscious  of  the  separate  sensa- 
tions which  guide  speech  or  writing ;  we  cannot  properly 
be  said  to  will  the  utterance  of  each  tone,  or  the  forma- 
tion of  each  letter.  Are  these  processes  mechanical  and 
not  volitional  ?  By  no  means.  We  know  that  they  were 
laboriously  learned  by  long  tentative  efforts,  each  of  which 
was  accompanied  by  distinct  consciousness.  We  also 
know  that  now  when  the  mechanism  is  so  easy  in  its 
adjustment  as  to  suggest  automatism,  there  needs  but  a 
slight  alteration  in  the  conditions  to  make  us  distinctly 
conscious  of  the  processes  —  the  wTong  word  spoken,  or 
one  hitter  ill  formed,  suffices  to  arrest  tlie  easy  working 
of  the  mechanism.  A  similar  mechanism  operates  in 
thinking,  wliich  also  lapses  from  the  conscious  and  volun- 
tary to  the  unconscious  and  involuntary  state.  The  logi- 
cal process  of  Judgment  is  as  purely  a  reflex  from  one 
neural  group  to  another,  as  the  physiological  process  of 
co-ordination.  In  ordinary  thinking  we  are  as  little  con- 
scious of  the  particular  steps  —  our  interest  being  concen- 
trated on  the  result  —  as  we  are  of  the  particular  stages 


426  THE   PHYSICAL   BASIS   OF   JIIXD. 

of  an  action.  The  adjustmelits  of  the  mechanism  of  Re- 
production and  Association  are  set  going  by  a  motive,  and 
kept  going  by  psychological  motors.  And  here  —  as  in 
bodily  actions  —  there  is  often  a  conflict  between  motive 
and  motors  —  between  the  foreseen  result,  and  the  avail- 
able means  of  reaching  it  —  the  motors  usually  prevailing 
because  they  represent  the  active  side  of  the  mechanism. 
Thus  when  an  oculist  wishes  to  examine  a  patient's  eye, 
he  does  not  tell  him  to  give  a  particular  direction  to  his 
eye,  knowing  that  the  motive  to  do  so  will  not  suflEice ; 
instead  of  this  he  simply  moves  his  own  hand  in  the  de- 
sired direction,  certain  that  the  eye  will  by  reflex  irresist- 
ibly follow  it.  Nay,  there  are  sometimes  such  anomalies 
of  innervation  that  the  eye,  instead  of  obeying  the  motive, 
moves  in  a  contrary  direction.  Meschede  mentions  a 
patient  whose  movements  were  mostly  of  this  anomalous 
kind :  when  he  willed  to  move  the  eyes  to  the  right,  they 
moved  to  the  left ;  when  he  willed  to  move  them  up,  they 
moved  down.  It  was  thus  also  with  his  hands  and  feet. 
Yet  he  was  distinctly  conscious  that  his  intention  had 
been  frustrated,  and  that  he  acted  "  because  he  could  not 
help  it."  *  How  insensibly  a  motive  sinks  into  a  motor, 
that  is  to  say,  a  voluntary  into  an  involuntary  act,  may  be 
recognized  in  speech,  writing,  singing,  walking,  etc.,  and 
in  the  incessant  movements  of  the  eye  in  fixing  objects. 
Aubert  has  Avell  remarked  that  we  only  give  definite 
movements  to  the  eye  when  we  wish  to  see  an  object 
distinctly.  Whenever  the  indistinct  vision  suffices  — 
as  in  walking  through  the  streets  occupied  in  conver- 
sation or  thought  —  we  make  no  such  movements ;  but 
no  sooner  does  any  object  excite  our  attention,  than 
the  effort  to  fix  that  object  at  once  excites  the  necessary 
reflex.f 

*  Allgemeine  Zeitschrift  filr  Psychiatric,  Bd.  31,  p.  711. 

t  Aubert,  Grundziigc  dcr  physiol.  Optik,  1876,  p.  633.      "The  accom- 


ANIMAL  AUTOMATISM.  427 

70.  By  the  Will,  then,  we  must  understand  the  abstract 
generalized  expression  of  the  impulses  which  determine 
actions,  when  those  impulses  have  an  ideal  origin ;  by 
Volition  the  still  more  generalized  expression  of  all  im- 
pulses wdiich  determine  actions.  The  one  class  is  that 
of  motives  with  ideal  elements ;  the  other  that  of  inotors 
vith  sensational  or  emotional  elements.  But  both  are 
nental  states,  both  are  neural  processes  in  a  sentient 
oi^anism ;  neither  is  mechanical,  except  in  so  far  as  all 
acions  are  expressible  in  mechanical  terms.  For  conven- 
ietce  we  class  actions  as  reflex,  automatic,  involuntary, 
untonscious,  voluntary,  and  conscious.  If  we  separate  the 
refltx  from  the  voluntary,  we  need  not  therefore  dissociate 
the  ^ormer  from  Sensibility ;  and  the  reason  why  we  ought 
not  to  separate  it  is  that  we  know  it  to  be  sense-guided 
from  first  to  last,  although  the  sensations  may  escape  dis- 
crimnation.  The  feeling  of  Effort,  which  was  formerly 
felt  vhen  an  action  was  performed,  may  have  become  so 
mininized  that  it  is  too  faint  for  more  than  a  momentary 

modatie  movement  of  the  eye  is  to  be  considered  voluntary.  It  is  true 
we  coni'act  the  pupil  without  being  conscious  of  the  contraction  of  mus- 
cular fires,  hut  this  holds  good  for  every  voluntary  movement.  When  a 
person  xises  the  tone  of  his  voice  he  is  not  conscious  that  by  muscular 
contracton  he  makes  his  chorda;  vocales  more  tense  ;  he  attains  his  ob- 
ject witout  being  aware  of  the  means  by  which  he  does  so.  The  same 
is  applicble  to  accommodation  for  near  objects  and  to  the  contraction  of 
the  pupi  accompanying  it.  The  fact  that  this  last  is  only  an  associated 
movemcn  does  not  deprive  it  of  its  voluntary  character,  for  there  is  per- 
haps no  ingle  muscle  which  can  contract  entirely  by  itself."  Donders, 
On  the  anomalies  of  Accommodation,  1864,  p.  574.  Professor  Beer  of 
Bonn  ha  the  rare  power  of  contracting  or  dilating  the  pupils  of  his  eye 
at  will  ;  lere  ideas  act  as  motors.  When  he  thinks  of  a  very  dark  space 
the  pupi  dilates,  when  of  a  very  bright  spot  the  pupil  contracts.  (No- 
ble, Tli  Human  Mind,  1858,  p.  124.)  I  believe  this  to  be  only  an 
fxaggera^d  form  of  the  normal  tendency.  In  all  of  us  the  mechanism 
is  so  (lispsed  that  the  feelings  of  dilatation  are  associated  with  feelings 
(and  conr-qucntly  ideas)  of  darkness  ;  and  by  this  association  a  reversal 
of  the  pjcess  obtains,  so  that  the  idea  of  darkness  calls  up  the  feeling  it 
symbolics. 


428  THE  niYsiCAL  basis  of  mind. 

consciousness,  too  evanescent  for  the  memory  to  retain  it ; 
yet  the  feeling  must  always  be  operant  when  its  mechan- 
ism is  in  action.  The  ease  with  which  the  mechanism 
works  does  not  change  the  adjustment  of  its  elements, 
nor  alter  its  character.  The  facile  unobtrusive  perform- 
ance of  a  vital  function  does  not  change  it  from  a  vital  ti) 
a  mechanical  act.  Mr.  Spencer  seems  to  me  to  express 
himself  ambiguously  when  he  says :  "  Just  as  any  set  «f 
psychical  changes  originally  displaying  Memory,  Eeasfn, 
and  Feeling  cease  to  be  conscious,  rational,  and  emotional 
as  fast  as  they  by  repetition  grow  closely  organized,  so  do 
they  at  the  same  time  pass  beyond  the  sphere  of  Voliton. 
Memory,  Eeason,  Feeling,  and  Will  disappear  in  propor- 
tion as  psychical  changes  become  automatic"*  —  for  \hi\v 
it  is  perfectly  true  that  we  only  call  those  psyclical 
changes  "automatic"  which  have  lost  the  special  quaities 
called  "conscious,  rational,  and  emotional,"  it  is  no'  less 
true  that  they  remain  from  first  to  last  psychical  chaiges, 
and  are  thereby  distinguished  from  physical  changes  To 
suppose  that  they  pass  from  the  psychical  to  the  plysical 
by  frequent  repetition  would  lead  to  the  monstrous  con- 
clusion that  when  a  naturalist  has  by  laborious  study 
become  so  familiarized  with  the  specific  marks  |of  an 
animal  or  plant  that  he  can  recognize  at  a  glancea  par- 
ticular species,  or  recognize  from  a  single  charaoer  the 
nature  of  the  rest,  the  rapidity  and  certainty  of  thi  judg- 
ment proves  it  to  be  a  mechanical,  not  a  mental  ac.  The 
intuition  with  which  a  mathematician  sees  the  olution 
of  a  problem  would  then  be  a  mechanical  proce^,  while 
the  slow  and  bungling  hesitation  of  the  tyro  in  jresence 
of  the  same  problem  would  be  a  mental  process:  he  per- 
fection of  the  organism  would  thus  result  in  its  (^grada- 
tion to  the  level  of  a  machine  ! 

The  operations  of  the  intellect  may  furnish  us  |ith  an 

*  Spencee,  Principles  of  Psychology,  I.  499. 


ANIMAL   AUTOMATISM.  429 

illustration.  Ideas  are  symbols  of  sensations.  The  idea 
of  a  horse  is  an  abstraction  easily  traceable  to  concrete 
sensations,  yet  as  an  abstraction  is  so  different  a  state  of 
feeling  that  we  only  identify  it  with  its  concretes  by  a 
careful  study  of  its  stages  of  evolution,  namely,  sensation, 
image,  reproduced  images  resembling  yet  differing  from 
the  original  sensation,  a  coalescence  of  their  resemblances, 
and  finally  the  substitution  of  a  verbal  symbol  for  these 
images.  With  this  symbol  the  intellect  operates,  and 
sometimes  operates  so  exclusively  with  it  that  not  the 
faintest  trace  of  image  or  sensation  is  appreciable  —  the 
word  horse  takes  the  place  of  the  image  in  the  sequence 
of  sensorial  processes,  just  as  the  image  takes  the  place  of 
the  sensation.  It  does  this  as  a  neural  equivalent.  In 
the  same  way  we  substitute  verbal  symbols  for  a  bag  of 
sovereigns  when  we  pay  a  creditor  with  a  check ;  he  pays 
the  check  away  to  another;  and  this  monetary  equivalent 
passes  from  hand  to  hand  without  a  single  coin  making  its 
appearance.  Does  the  transaction  cease  to  be  commercial, 
monetary,  in  this  substitution  of  signs  ?  No  ;  nor  does  a 
process  cease  to  be  psychical  when  an  image  is  substituted 
for  a  sensation,  and  a  verbal  symbol  for  an  image.  This 
every  one  will  admit.  Must  we  not  go  further,  and  ex- 
tend tlie  admission  to  automatic  actions  which  originally 
were  voluntary,  and  have  now  lost  all  trace  of  ideal  pre- 
vision, and  almost  all  traces  of  accompanying  conscious- 
ness ?  The  motor  mechanism  has  its  si/mhofs  also ;  in  this 
sense,  that  whereas  the  action  which  at  first  needed  com- 
plex sensorial  processes  to  set  it  going  and  keep  it  going, 
is  now  determined  by  a  single  one  of  those  processes 
taking  the  place  of  their  resultant.  When  a  practised 
accountant  runs  his  eye  up  a  column  of  figures,  he  does 
not  pause  to  realize  the  values  of  those  figures  by  decom- 
posing the  symbols  into  their  numerical  units,  lie  simply 
groups  one  symbol  with  another  according  to  their  intuited 


430  THE  PHYSICAL   BASIS   OF   MIND. 

relations,  and  the  final  result  is  reached  with  a  certainty 
not  less,  and  a  rapidity  far  greater,  than  if  it  had  been 
reached  by  step-by-step  verification.  It  is  thus  with  the 
pianoforte-player.  It  is  thus  with  all  automatic  perform- 
ances, except  those  dependent  on  the  connate  adjustments 
of  the  mechanism. 


ANIMAL  AUTOMATISM.  431 


CHAPTEE  VI. 

THE   PKOBLEM  STATED. 

71.  If  the  preceding  attempt  to  disengage  the  question 
from  the  ambiguities  of  its  terms  has  been  successful, 
we  shall  find  little  difficulty  in  rationally  interpreting  all 
the  facts  adduced  in  favor  of  Animal  Automatism,  with- 
out having  recourse  to  a  mechanical  theory  of  biological 
phenomena.  The  objections  to  that  theory  are  that  it 
employs  terms  which  have  very  misleading  connotations 
even  when  they  do  not  denote  phenomena  of  widely  differ- 
ent orders ;  so  that  the  moral  repugnance  commonly  felt 
at  the  attempt  to  treat  the  animal  organism  as  if  it  were 
a  machine,  is  sustained  by  the  intellectual  repugnance  at 
the  attempt  to  explain  biological  phenomena  on  princi- 
ples derived  from  phenomena  of  a  simpler  order. 

Eemark,  in  passing,  this  piquant  contradiction :  the 
Automaton  theory  of  Descartes,  when  applied  to  the  ani- 
mals, generally  excited  ridicule  or  repulsion  ;  whereas  the 
far  more  inconsistent  and  mechanical  theory  of  Eeflex 
Action  has  been  almost  universally  welcomed  as  a  great 
discovery,  though  it  banishes  the  Sensibility  which  Des- 
cartes preserved.  And  further,  the  philosophers  who 
most  loudly  protested  against  the  idea  that  animals  were 
machines,  were  the  philosophers  who  most  insisted  that 
these  animals  were  made,  not  evolved  —  planned  by  their 
maker,  as  a  watch  is  planned  by  its  maker,  with  a  dis- 
tinct purpose  and  prevision  in  the  disposition  of  every 
part;  whereas  the  philosophers  who  most  emphatically 


432  THE  rnYSicAL  basis  of  mind. 

reject   this   notion  of  organisms  being  made,  are  often 
those  who  liken  organisms  to  machines. 

72.  The  paradox  propounded  by  Descartes  loses  much 
of  its  strangeness  when  we  understand  his  meaning.  Its 
terms  are  infelicitous  because  of  their  misleading  conno- 
tations. When  he  says  that  all  the  actions  of  animals 
which  seem  to  be  due  to  Consciousness  are  in  fact  pro- 
duced on  the  same  principles  as  those  of  a  machine,  he 
means  that  animals  have  not  souls  to  direct  their  actions ; 
but  since,  on  being  questioned,  he  is  ready  to  admit  that 
animals  have  sensation,  perception,  emotion,  and  memory, 
his  denial  of  their  souls  practically  comes  to  much  the 
same  as  the  ordinary  position  that  animals  have  not 
Thought  nor  Consciousness  of  Self.*  The  admission  of 
sensation  is,  however,  quite  enough  to  mark  the  essential 
difference  between  an  organism  and  a  machine. 

73.  It  was  really  a  great  step  taken  by  Descartes  when 
he  directed  attention  to  the  fact  that  all  animal  actions 
were  executed  in  strict  conformity  with  mechanical  prin- 
ciples, because  both  before  his  time,  and  since,  we  may 
observe  a  great  disregard  of  the  animal  mechanism,  and  a 
disposition  to  interpret  the  phenomena  on  metaphysical 
principles.     But  the  connotations  of  the  term  "  machine  " 

*  Descartes  expressly  calls  them  sensitive  machines.  He  refuses 
them  Thought,  but  neither  "la  vie  ou  le  sentiment."  He  adds,  "Mon 
opinion  n'est  pas  que  les  betes  Toient  comme  nous  lorsque  nous  sentons 
que  nous  voyons."  —  (Euvrcs,  IV.  p.  339.  This  example  is  cited  by  him 
in  proof  of  human  automatism:  "Que  ce  n'est  point  par  I'entremise  dc 
notre  ame  que  les  yeux  se  fennent,  puisque  c'est  contre  notre  volonte, 
laquelle  est  sa  seule  ou  du  moins  sa  principale  action  ;  mais  c'est  a  cause 
que  la  machine  de  notre  corps  est  tellement  composee  que  le  mouvement 
de  cette  main  vers  nos  yeux  excite  un  autre  mouvement  en  notre  cerveau 
qui  conduit  les  esprits  animaux  dans  les  muscles  qui  font  abaisser  les 
paupieres."  All  indeed  that  we  assign  to  Sensibility,  he  assigns  to  these 
hypothetical  animal  spirits,  and  thence  he  concludes,  "Qu'il  ne  reste 
rien  en  nous  que  nous  devions  attribuer  a  notre  ame  sinon  nos  pensees." 
—  Les  Passions  de  VAme,  art.  13  and  17.  Comp.  Discours  de  la  Melhode, 
partie  iv. 


ANIMAL   AUTOMATISM.  433 

were  such  as  to  lead  tlie  mind  away  from  the  special  con- 
ditions of  the  vital  mechanism,  and  fix  it  exclusively  on 
the  general  conditions  of  macliinery.  Hence  his  oppo- 
nents misunderstood  him,  and  some  of  his  followers  made 
the  same  oversight,  and  ended  by  eliminating  sensation 
altogether.  In  pursuance  of  this  mechanical  point  of 
view,  to  the  exclusion  of  the  biological,  Thouglit  and  even 
Consciousness  have  been  eliminated  from  among  the  or- 
ganic agencies,  and  are  said  to  have  no  more  influence  in 
determining  even  human  actions  than  the  whistle  of  the 
steam-engine  has  in  directing  the  locomotive.  There  are 
thus  two  ?Hc/faphysiological  theories.  According  to  the  ' 
one,  Consciousness  directs  indeed  the  actions  of  the  organ- 
ism, but  is  not  itself  an  organic  process  —  it  sits  apart, 
like  a  musical  performer  playing  on  an  instrument.  Ac- 
cording to  the  other,  it  is  not  a  directing  agency,  but  an 
accessory  product  of  certain  organic  processes,  which  pro- 
cesses may  go  on  quite  as  well  without  any  accompani- 
ment and  interference  of  Consciousness. 

74.  Two  observations  arise  here.  First,  we  observe  a 
want  of  due  recognition  of  the  objective  and  subjective 
aspects,  and .  their  respective  criteria.  Secondly,  we  ob- 
serve mental  facts  of  irresistible  certainty  interpreted  by 
material  hypotheses  of  questionable  value ;  and  not  only 
so,  but  a  higlier  validity  is  assigned  to  the  material 
hypotheses  than  to  the  mental  facts  they  are  invented 
to  explain.  That  we  are  conscious,  and  that  our  actions 
are  determined  by  sensations,  emotions,  and  ideas,  are 
I'acts  which  may  or  may  not  be  explained  by  reference  to 
material  conditions,  but  which  no  material  explanation 
can  render  more  certain.  That  animals  resemljle  us  in 
this  as  in  other  respects  is  an  induction  of  the  highest 
]trobability.  It  is  also  a  fact  that  many  actions  take 
place,  as  we  say,  unconsciously  and  involuntarily;  and 
tliat  some  take  place  now^sonsciously,  now  unconsciously. 

VOL.    III.  19  BB 


434  THE  niYsiCAL  basis  of  mind. 

These  facts  also  we  endeavor  to  explain :  and  when  we 
find  that  some  of  the  unconscious  and  involuntary  actions 
take  place  after  the  brain  has  been  removed,  this  is  inter- 
preted on  the  material  hypothesis  of  the  brain  being  the 
sole  seat  of  sensation  and  consciousness ;  and  is  urged  in 
favor  of  the  hypothesis  that  consciousness  cannot  be  an 
agent  in  the  mechanism.  Here  the  confusion  of  objective 
and  subjective  aspects  is  patent.  Consciousness  as  a  sub- 
jective fact  cannot  be  a  material  or  objective  fact.  But 
may  it  not  be  another  aspect  of  that  which  is  objective  ? 
So  long  as  we  are  dealing  with  the  objective  aspect,  we 
have  nothing  but  material  processes  in  a  material  mech- 
anism before  us.  A  change  within  the  organism  is  caused 
by  a  neural  stimulation,  and  the  resulting  action  is  a  re- 
flex on  the  muscles.  Here  there  is  simply  a  transference 
of  motion  by  a  material  mechanism.  There  is  in  this  no 
evidence  of  a  subjective  agency ;  there  could  be  none. 
But  when  we  come  to  investigate  the  process,  ^ve  find 
that  it  differs  from  similar  processes  in  anorganisms,  by 
the  necessary  co-operation  of  special  conditions,  and  among 
these  —  the  vital  conditions  —  there  are  those  which  in 
their  subjective  aspect  we  express  not  in  terms  of  INIatter 
and  Motion,  but  in  terms  of  Feeling,  i.  e.  not  in  objective 
but  in  subjective  terms.  I  see  a  stone  move  on  being 
struck  ;  I  also  see  a  man  shrink  on  being  struck,  and  hear 
a  dog  howl  on  being  kicked.  I  do  not  infer  that  the  stone 
feels  as  the  man  and  dog  feel,  because  I  know  the  stone  and 
the  dog"  to  be  differently  constituted,  and  infer  a  corre- 
sponding difference  in  their  reactions.  I  infer  that  the 
man  and  dog  feel,  because  I  know  they  are  like  myself, 
and  conclude  that  what  I  feel  they  feel,  under  like  con- 
ditions. 

75.  Descartes  says  that  animals  are  sensitive  automata. 
They  always  act  as  we  sometimes  act,  i.  e.  when  we  are  not 
conscious  of  what  we  do,  as  in*  singing,  walking,  playing 


ANIMAL   AUTOMATISM.  435 

the  piano,  etc.  We  are  said  to  do  these  things  mechan- 
ically, automatically,  and  hence  the  conclusion  that  these 
actions  are  those  of  a  pure  mechanism.  But  it  would  be 
truer  to  say  that  we  never  act  mechanically,  w^e  always 
act  organically.  "When  one  who  falls  from  a  height 
throws  his  hands  forwards  to  save  his  head,"  says  Des- 
cartes, "it  is  in  virtue  of  no  ratiocination  that  he  per- 
forms this  action  "  (that  depends  on  the  definition  :  in  the 
Logic  of  Feeling  there  is  a  process  of  ratiocination  iden- 
tical with  that  in  the  Logic  of  Signs).  "  It  does  not 
depend  upon  his  mind  "  (again  a  question  of  definition), 
"  but  takes  place  merely  because  his  senses  being  affected 
hy  present  clanger"  (senses,  then,  have  a  perception  of 
danger  ?)  "  some  change  arises  in  his  brain  which  deter- 
mines the  animal  spirits  to  pass  thence  into  the  nerves 
in  such  a  manner  as  is  required  to  produce  this  motion, 
in  the  same  way  as  in  a  machine,  and  without  his  mind 
being  able  to  hinder  it.  Now  since  we  observe  this  in 
ourselves,  why  should  we  be  so  much  astonished  if  the 
light  reflected  from  the  body  of  a  wolf  into  the  eye  of  a 
sheep  has  the  same  force  to  excite  in  it  the  motion  of 
flight  ? " 

Here,  both  in  the  case  of  the  man  and  the  sheep,  there  is 
presupposed  the  very  mental  experience  which  is  denied. 
The  young  child  will  not  throw  out  its  arm  to  protect 
itself;  but  after  many  experiences  of  falling  and  stum- 
Jjling,  there  is  an  organized  perception  of  the  impending 
danger,  and  the  means  of  averting  it,  and  it  is  this  which 
determines  the  throwing  out  of  the  arms.  If  this  is  not 
a  mental  fact  —  a  process  of  judgment  —  then  the  logical 
conclusion  by  which  a  financier  on  hearing  a  war  rumor 
orders  his  broker  to  sell  stock,  is  not  a  mental  fact.  The 
light  reflected  from  the  body  of  a  wolf  would  not  disturb 
the  sheep  unless  its  own,  or  its  inherited  organized  expe- 
rience were  ready  there  to  respond.     But  this  organized 


436  THE    PHYSICAL   BASIS   OF   MIND. 

experience,  you  say,  enters  into  the  mechanism  ?  Yes ; 
but  it  cannot  be  made  to  enter  into  the  mechanism  of  an 
automaton,  because  however  complex  that  mechanism 
may  be,  and  however  capable  of  variety  of  action,  it  is 
constructed  solely  for  definite  actions  on  calculated  lines : 
all  its  readjustments  must  have  been  foreseen,  it  is  in- 
capable of  adjusting  itself  to  unforeseen  circumstances. 
Hence  every  interruption  in  the  prearranged  order  either 
throws  it  out  of  gear,  or  brings  it  to  a  standstill.  It  is 
regulated,  not  self-regulating.  The  organism,  on  the  con- 
trary —  conspicuously  so  in  its  more  complex  forms  —  is 
variable,  self -regulating,  incalculable.  It  has  selective 
ndaptation  (p.  221)  responding  readily  and  efficiently  to 
novel  and  unforeseen  circumstances;  acquiring  new  modes 
of  combination  and  reaction.  An  automaton  that  will 
learn  by  experience,  and  adapt  itself  to  conditions  not 
calculated  for  in  its  construction,  has  yet  to  be  made ; 
till  it  is  made,  we  must  deny  that  organisms  are  ma- 
chines. Automatism  in  the  organism  implies  Memory 
and  Perception.  A  sudden  contact — a  sudden  noise  —  a 
vague  form  seen  in  the  twilight  will  excite  the  mechan- 
ism according  to  its  organized  experiences.  We  start 
automatically,  before  we  automatically  interpret  the  cause ; 
w^e  start  first,  and  then  ask.  What  is  that  ?  But  we  do 
not  always  start  at  sounds  or  sights  which  have  no  asso- 
ciation with  previous  experiences.  The  child  and  the  man 
both  see  the  falling  glass,  but  the  child  does  not  automat- 
ically stretch  out  a  hand  to  save  the  glass.  Having  once 
learned  the  action  of  swimming  or  billiard-playing,  we 
automatically  execute  these ;  without  consciously  remem- 
bering the  rules,  we  unconsciously  obey  them  ;  each  feel- 
ing as  it  rises  is  linked  on  to  another,  each  muscle  is 
combined  with  others  in  a  remembered  synthesis. 

76.    Kempelen's  chess-player  surprised  the  public,  but 
every  instructed  physiologist  present  knew  that  in  some 


ANIMAL   AUTOMATISM.  437 

way  or  other  its  movements  were  directed  by  a  human 
mind ;  simply  because  no  machine  could  possibly  have 
responded  to  the  unforeseen  fluctuations  of  the  human 
mind  opposed  to  it.  Even  the  mind  of  a  dog  or  a  savage 
would  be  incompetent  to  pass  beyond  the  range  of  its  pre- 
vious experiences,  incompetent  to  seize  the  significance 
of  an  adversary's  moves  on  the  chessboard.  Now  just  as 
we  conclude  that  mental  agency  is  essential  to  a  game 
of  chess,  so  we  conclude  that  Sensibility  is  essential  to 
the  fluctuating  responses  of  an  organism  under  ^^nforeseen 
circumstances.  We  can  conceive  an  automaton  dog  that 
would  bark  at  the  presence  of  a  beggar ;  but  not  of  an  au- 
tomaton dog  that  would  bark  one  day  at  the  beggar  and  the 
next  day  wag  his  tail,  remembering  the  food  and  patting 
that  beggar  had  bestowed.  Since  all  we  know  of  machines 
forbids  the  idea  of  their  being  capable  of  adjusting  their 
actions  to  new  circumstances,  or  of  evoking  through  ex- 
perience new  powers  of  combination,  we  conclude  that 
wherever  this  capability  of  adaptation  is  present  there  is 
an  agency  in  operation  which  does  not  belong  to  the 
class  of  mechanical  agencies.  Goltz  has  shown  that  a  frog 
deprived  of  its  brain  manifests  so  much  of  vision  as  en- 
ables it  to  avoid  obstacles  —  leaping  to  the  right  or  to 
the  left  of  a  book  placed  in  its  path.  This  Professor 
Huxley  regards  as  purely  mechanical:  —  "Although  the 
•frog  appears  to  have  no  sensation  of  light,  visible  objects 
act  upon  the  motor  mechanism  of  its  body."  Should  we 
not  rather  conclude  that  if  the  frog  had  no  sensation,  no 
such  effect  would  follow  ?  because  although  a  machine 
mifjld  be  constructed  to  respond  to  variations  of  light  and 
sliadows,  none  could  be  constructed  (without  Sensibility) 
to  respond  to  the  fluctuating  conditions  as  an  organism 
responds.*    AVere  the  reflex  actions  of  the  organism  purely 

*  I)IvS(;aiites  compares  tlie  animal  mechanism  to  that  of  tho  grottos 
and  fountains  at  Versailles,  the  nerves  to  the  water-tubes :  —  "  Les  objets 


438  THE   PHYSICAL   BASIS   OF   MIND. 

mechanical  —  i.  e.  involving  none  of  those  fluctuating 
adjustments  whicli  characterize  Sensibility  —  the  effect 
vould  be  uniform,  and  proportional  to  the  impact ;  but  it 
is  variable,  and  proportional  to  the  static  condition  of  the 
nervous  centres  at  the  moment.  Exaggerate  this  —  by 
strychnine,  for  instance  —  and  the  slightest  touch  on  the 
skin  will  produce  general  convulsions.  Lower  it  —  by  an 
anaesthetic  —  and  no  reflex  at  all  will  follow  a  stimulus. 
In  anesthesia  of  the  mucous  membrane,  no  reflex  of  the 
eyelid,  no  secretion  of  tears,  follows  on  the  irritation  of 
the  membrane ;  no  sneezing  follows  irritation  of  the  in- 
side of  the  nose ;  no  vomiting  follows  irritation  of  the 
fauces. 

77.    The  question  has  long  ceased  to  be  whether  the 
organism  is  a  mechanism.     To  the  physiologist  it  is  this 

exterieuvs  qui  par  leiir  seul  presence,  agissent  contra  les  organes  des  .sens, 
et  qui  par  ce  moyen,  la  duterminent  a  se  mouvoir  en  plusieurs  diverses 
fa9ons,  selon  comme  les  parties  du  cerveau  sont  disposees,  sont  conime  les 
etrangers,  qui  entrant  dans  quelques  unes  des  grottes  de  ces  fontaines 
causent  euxmemes  sans  y  penser  les  mouvements  qui  s'y  font  en  leur 
presence  :  car  ils  u'y  peuvent  entrer  qu'en  marchant  sur  certains  carreaux 
tellement  disposes,  que  s'ils  approchent  d'une  Diane  qui  se  baigne,  ils  la 
font  cacher  dans  les  roseaux  ;  et  s'ils  passent  outre  pour  la  poursuivre,  ils 
feront  venir  vers  eux  un  Neptune  qui  les  menacera  de  son  trident ;  ou  s'ils 
vont  de  quelque  autre  coste,  ils  en  feront  sortir  un  monstre  marin  qui  leur 
vomira  de  I'eau  contra  la  face." —  Traiti  de  T Homme,  1664,  p.  12.  In- 
genious as  the  comparison  is,  it  only  illustrates  how  machines  may  be 
constructed  to  imitate  animal  actions.  Diana  always  hides  herself  when 
a  certain  spot  is  trodden  upon  ;  and  Neptune  always  appears  when  an- 
other spot  is  trodden  upon.  There  is  no  fluctuation,  no  sensibility  dis- 
cerning differences  and  determining  variations.  Compare  the  following 
experiment :  A  monkey  was  placed  on  the  table  and  a  shrill  whi.stle  made 
close  to  its  ear :  "  Immediately  the  ear  was  pricked  and  the  animal  turned 
with  an  air  of  intense  surprise,  with  eyes  widely  opened  and  jiupils 
dilated,  to  the  direction  whence  the  sound  proceeded.  On  repetition  of 
the  experiment  several  times,  though  the  pricking  of  the  ear  and  the 
turning  of  the  head  and  eyes  constantly  occurred,  the  look  of  surprise 
and  dilatation  of  the  pupils  ceased  to  be  manifested." — Ferrier, 
The  Functions  of  the  Brain,  1876,  p.  171.  A  mechanical  monkey  would 
always  have  reacted  in  precisely  the  same  way  on  each  stimulus. 


ANIMAL   AUTOMATISM.  439 

before  all  things.  To  the  psychologist  also  it  has  of  late 
years  more  and  more  assumed  this  character;  because  even 
when  he  postulates  the  existence  of  a  spiritual  entity  in 
the  organism  but  not  of  it,  he  still  recognizes  the  neces- 
sity of  a  mechanism  for  the  execution  of  the  acts  deter- 
mined by  the  spirit ;  and  when  the  psychologist  adopts 
the  theory  of  spiritual  phenomena  as  the  subjective  aspect 
of  what  objectively  are  material  phenomena,  he  of  course 
regards  the  bodily  mechanism  and  the  mental  mechanism 
as  one  and  the  same  real. 

This  settled,  the  problem  of  Automatism  may  be  thus 
stated :  Granting  the  animal  organism  to  be  a  material 
mechanism,  and  all  its  actions  due  to  the  operation  of 
that  mechanism,  are  we  to  conclude  that  it  is  an  autom- 
aton essentially  resembling  the  automata  we  construct, 
the  movements  of  which  may,  or  may  not,  be  accompanied 
by  Feeling,  but  are  in  no  case  determined  by  Feeling  ? 

Descartes  says  that  animals  are  sensitive  automata. 
Professor  Huxley  says  that  both  animals  and  men  are 
sensitive  and  conscious  automata ;  so  that  misleading  as 
the  language  of  Descartes  and  Professor  Huxley  often 
is  in  what  its  terms  connote,  we  do  them  great  injustice  if 
we  suppose  them  to  have  overlooked  the  points  of  differ- 
ence between  organisms  and  machines  which  have  been 
set  forth  with  so  much  emphasis  in  a  preceding  chapter ; 
and  the  reader  is  requested  to  understand  that  without 
pretending  to  say  how  much  the  inevitable  connotation 
of  their  language  expresses  their  opinions,  and  how  much 
it  may  have  only  led  to  their  being  misunderstood,  my 
criticisms  are  directed  against  this  connotation  and  this 
interpretation. 


440  THE  PHYSICAL  BASIS   OF  MIND. 


CHAPTER    VII. 

IS  FEELING  AN   AGENT? 

78.  Descartes  having  attributed  all  animal  actions  to 
a  sensitive  mechanism,  and  indeed  all  human  actions  to  a 
similar  mechanism,  endeavored  to  reconcile  this  hypoth- 
esis with  the  irresistible  facts  of  Consciousness  —  which 
assured  us  that  our  actions,  at  least,  were  determined  by 
Feeling.  To  this  end  he  assumed  that  man  had  a  spirit- 
ual'principle  over  and  above  the  sentient  principle.  The 
operation  of  this  principle  was,  however,  limited  to  Thought; 
the  actions  themselves  were  all  performed  by  tlie  auto- 
matic mechanism ;  so  that,  in  strict  logic,  the  conclusion 
from  his  premises  was  the  same  for  man  as  for  animals. 

This  conclusion  Professor  Huxley  announced  in  his 
Address  before  the  British  Association,  1874*  —  to  the 
great  scandal  of  the  general  public,  which  did  not  under- 
stand him  aright ;  and  to  the  scandal  also  of  a  physiologi- 
cal public,  which,  strangely  enough,  failed  to  see  that  it 
was  the  legitimate  expression  of  one  of  their  favorite 
theories  —  the  celebrated  Picflex  Theory.  Now  although 
it  is  quite  open  to  any  one  to  reject  the  premises  which 
lead  to  such  a  conclusion,  if  he  sees  greater  evidence 
against  the  conclusion  than  for  the  premises,  it  is  surely 
irrational  to  accept  the  premises  as  those  of  scientific  in- 
duction, and  yet  reject  the  conclusion  because  it  endan- 
gers the  stability  of  other  opinions  ?     For  my  own  part, 

*  Printed  in  the  FortnigJUly  Eevicw,  November,  1874,  from  which  all 
my  citations  are  made. 


ANIMAL  AUTOMATISM. 


441 


I  do  not  accept  the  premises,  and  my  polemic  will  have 
reference  to  them. 

79.  Professor  Huxley  adopts  certain  Theses  which 
represent  the  views  generally  adopted  by  physiologists ; 
to  which  he  adds  a  Thesis  which  is  adopted  by  few,  and 
which  he  only  puts  forward  hypothetically.  Against 
these  positions  I  place  Antitheses,  less  generally  adopted, 
but  which  in  my  belief  approximate  more  nearly  to  the 
inductions  of  experience. 


Theses. 

I.  There  can  be  no  sensation 
without  consciousness. 

II.  There  can  be  no  conscious- 
ness without  the  co-operation  of 
the  brain. 

III.  Sensation  and  Conscious- 
ness are  in  some  inexplicable  way 
caused  by  molecular  changes  in  the 
brain,  following  upon  these  as  one 
event  follows  another,  the  causal 
link  between  motion  and  sensation 
being  a  mystery. 


IV.  All  actions  which  take  place 
unconsciously  are  reflex,  and  reflex 
actions  are  the  operation  of  an  in- 
sentient mechanism  ;  they  are  there- 
fore as  purely  mechanical  as  those 
of  automata. 

V.  The  animal  body  is  a  reflex 
mechanism  ;  even  when  the  brain 
co-operates  with  the  other  centres, 
and  produces  consciousness,  this 
])roduct  is  not  an  agent  in  deter- 
mining action,  it  is  a  collateral  re- 
sult of  the  operation. 

19* 


Antitheses. 

I.  There  is  sensation  without 
consciousness,  if  consciousness 
means  a  special  mode  of  Sentience. 

II.  The  co-operation  of  the  brain 
is  only  necessary  for  a  special  mode 
of  Sentience  ;  other  modes  are  ac- 
tive when  the  brain  is  inactive. 

III.  Unless  the  molecular 
changes  be  limited  to  the  brain  as 
the  occasioned  cause,  there  is  no 
following  of  sensation  or  motion, 
no  causal  link  between  the  two  ; 
but  the  neural  process  is  the  sen- 
sation, viewed  objectively,  the 
sensation  is  the  neural  process, 
viewed  subjectively.  In  this  an- 
tithesis, Neural  Process  is  not  lim- 
ited to  the  brain,  but  comprises 
the  whole  sensitive  organism  as  the 
efficient  cause. 

IV.  All  actions  are  the  actions 
of  a  reflex  mechanism,  and  all  are 
sentient,  even  when  unconscious  ; 
they  are  therefore  never  purely 
mechanical,  but  always  organical. 

V.  Sentience  being  necessary  to 
reflex  action,  it  is  necessarily  an 
agent. 


442  THE   PHYSICAL  BASIS   OF  MIND. 

80.  The  first  four  Theses  are  those  current  in  our  text- 
books, so  that  it  is  only  the  fifth  which  will  have  the  air 
of  a  paradox.  Nor,  as  a  paradox,  is  it  without  advocates. 
Schiff  long  ago  suggested  it  hypothetically.  Hermann 
mentions  it  as  entertained  by  physiologists,  whom  he 
does  not  name.*  Laycock,  and,  if  I  remember  rightly. 
Dr.  Drysdale,  have  insisted  on  it ;  and  Mr.  Spalding  has 
proclaimed  it  with  iterated  emphasis.  Of  the  Antitheses 
nothing  need  be  said  here,  since  the  whole  of  this  volume 
is  meant  to  furnish  their  evidence. 

I  have  already  stated  that  my  polemic  is  against  the 
views  that  Professor  Huxley  is  siqjposed  to  hold  by  those 
whom  his  expressions  mislead,  rather  than  against  the 
views  I  imagine  him  really  to  hold.  I  have  little  doubt 
that  he  would  disavow  much  that  I  am  forced  to  combat, 
although  his  language  is  naturally  interpreted  in  that 
sense.  But  I  do  not  know  in  how  far  he  would  agree 
with  me,  and  in  the  following  remarks  I  shall  confine 
myself  to  what  seems  to  be  the  plain  interpretation  of  his 
words,  since  that  is  the  interpretation  which  has  been 
generally  adopted,  and  which  I  most  earnestly  desire 
to  refute. 

81.  To  begin  with  this  passage.  After  stating  the 
views  of  Descartes,  he  says :  "  As  actions  of  a  certain  de- 
gree of  complexity  are  brought  about  by  mere  mechanism, 
why  may  not  actions  of  still  greater  complexity  be  the 
result  of  a  more  refined  mechanism  ?  "What  proof  is  there 
that  brutes  are  other  than  a  superior  race  of  marionnettes, 
which  eat  without  pleasure,  cry  without  pain,  desire  noth- 
ing, know  nothing,  and  only  simulate  intelligence  as  a 
bee  simulates  a  mathematician  ? "  Wliat  proof  ?  Why, 
in  the  first  place,  the  proof  which  is  implied  in  the  "  more 
refined  mechanism "  required  for  the  greater  complexity 

*  ScHiFF,  Lehrhuch  der  Physiol.,  1858,  p.  212.     Hermaxn,  Physiol- 
ogy, translated  by  Gamgee,  1875,  p.  511. 


ANIMAL   AUTO.MATISM.  443 

of  actions.  In  the  next  place,  the  proof  that  the  organism 
of  the  brute  is  very  different  from  the  mechanism  of  a 
marionnette,  and  is  so  much  more  like  the  organism  of 
man,  that  since  we  know  man  to  eat  with  pleasure  and 
cry  with  pain,  there  is  a  strong  presumption  that  the 
brute  eats  and  cries  with  somewhat  similar  feelings. 

82,  Having  stated  the  hypothesis,  Professor  Huxley 
says  he  is  not  disposed  to  accept  it,  though  he  thinks  it 
cannot  be  refuted.  His  chief  reason  for  not  accepting 
it  is  that  the  law  of  continuity  forbids  the  supposition  of 
any  complex  phenomenon  suddenly  appearing ;  the  com- 
munity between  animals  and  men  is  too  close  for  us  to 
admit  that  Consciousness  could  appear  in  man  without 
liaving  its  beginnings  in  animals.  Finding  that  animals 
have  brains,  he  justly  concludes  that  they  also  must  have 
brain  functions ;  and  they  also  therefore  must  be  credited 
with  Consciousness.  This  argument  seems  to  me  to  have 
irresistible  cogency  ;  and  to  be  destructive  not  only  of  the 
automaton  hypothesis,  but  equally  of  the  hypothesis  on 
which  tlie  Reflex  Theory  is  founded.  If  the  law  of  con- 
tinuity forbids  the  sudden  appearance  of  Consciousness, 
the  law  of  similarity  of  property  with  similarity  of  struc- 
ture forbids  the  supposition  that  central  nerve-tissue  in 
one  part  of  the  system  can  suddenly  assume  a  totally 
different  property  in  another  part.  If  the  brain  of  an 
animal,  a  bird,  a  reptile,  or  a  fish  —  and  a  fortiori  if  the 
oesophageal  ganglia  of  an  insect  or  a  mollusc  —  may  be 
credited  with  Sensibility,  because  of  the  fundamental 
similarity  of  these  structures  with  tlie  structures  of  the 
human  brain,  then  surely  the  spinal  cord  must  be  credited 
with  Sensibility ;  for  the  tissue  of  the  spinal  cord  is  more 
like  that  of  the  brain,  than  the  brain  of  a  reptile  is  like 
the  brain  of  a  man.  The  sudden  disappearance  of  all  Sen- 
sibility, on  tlie  removal  of  one  portion  of  tlie  central  ner- 
vous system,  would  be  a  violation  of  the  law  of  continuity. 


444  THE  niYsiCAL  basis  of  mind. 

And  if  it  be  said  that  Consciousness  is  not  the  same  as 
Sensibility,  but  is  a  specially  evolved  function  of  a  spe- 
cially developed  organ,  the  answer  will  be  that  this  is  only 
a  dilference  of  mode,  and  that  the  existence  of  Sensibility 
is  that  which  renders  the  automaton  and  reflex  theories 
untenable. 

83.  Professor  Huxley  would  probably  admit  this ;  for 
however  his  language  may  at  times  seem  to  point  to 
another  conclusion,  and  is  so  far  ambiguous,  he  has  ex- 
pressed the  view  here  maintained  with  tolerable  distinct- 
ness in  the  following  passage,  to  which  particular  attention 
is  called :  — 

"  But  though  we  may  see  reason  to  disagree  with  Des- 
cartes' hypothesis,  that  brutes  are  unconscious  machines, 
it  does  not  follow  that  he  was  wrong  in  regarding  them 
as  automata.  They  may  he  more  or  less  conscious  sensitive 
automata;  and  the  view  that  they  are  such  conscious 
machines  is  that  which  is  implicitly  or  explicitly  adopted 
by  most  persons.  When  we  speak  of  the  actions  of  the 
lower  animals  being  guided  by  instinct  and  not  by  reason, 
what  we  really  mean  is  that  though  they  feel  as  we  do, 
yet  their  actions  are  the  results  of  their  physical  organiza- 
tion. We  believe,  in  short,  that  they  are  machines,  one 
part  of  which  (the  nervous  system)  not  only  sets  the  rest 
in  motion  and  co-ordinates  its  movements  in  relation  with 
changes  in  surrounding  bodies,  but  is  provided  with  a 
special  apparatus  the  function  of  which  is  the  calling  into 
existence  of  those  states  of  consciousness  which  are  termed 
sensations,  emotions,  and  ideas." 

84.  To  say  that  they  are  "  conscious  automata  "  seems 
granting  all  that  I  demand  ;  but  there  are  two  objection- 
able positions  which  the  phrase  conceals :  first,  that  Con- 
sciousness is  not  a  coefficient ;  and  secondly,  that  Eeflex 
Action  is  purely  mechanical. 

Professor  Huxley  nowhere,  I  think,  establishes  the  dis- 


ANIMAL  AUTOMATISM.  445 

tinction  between  Consciousness  as  a  term  for  a  special 
mode  of  Feeling,  and  Consciousness  as  the  all-embracing 
term  for  sentient  phenomena.  His  language  always  im- 
plies that  an  action  performed  unconsciously  is  performed 
mechanically  ;  which  may  be  acceptable  if  by  uncon- 
sciously be  meant  insentiently.  I  liold  that  whether 
consciously  or  unconsciously  performed,  tlie  action  is 
equally  vital  and  sentient.  In  the  case  he  lias  cited  of 
a  soldier  now  living  who  is  subject  to  periodic  alterna- 
tions of  normal  and  abnormal  states,  in  the  latter  states 
all  the  actions  being  said  to  be  "  unconscious,"  we  have 
only  to  read  the  account  to  recognize  ample  evidence  of 
Sentience.     Here  is  a  descriptive  passage  :  — 

85.  "  His  [the  soldier's  in  the  abnormal  state]  move- 
ments remain  free,  and  his  expression  calm,  except  for  a 
contraction  of  the  brow,  an  incessant  movement  of  the 
eyeballs,  and  a  chewing  motion  of  the  jaws.  The  eyes 
are  wide  open,  and  their  pupils  dilated.  If  the  man  hap- 
pens to  be  in  a  place  to  which  he  is  accustomed  he  walks 
about  as  usual ;  but  if  he  is  in  a  new  place,  or  if  obstacles 
are  intentionally  placed  in  his  way,  he  stumbles  against 
them,  s/o|w,  and  thenfcclinrf  over  the  objects  ivith  his  hands, 
passes  on  one  side  of  them.  He  offers  no  resistance  to  any 
change  of  direction  which  may  be  impressed  upon  him, 
or  to  the  forcible  acceleration  or  retardation  of  his  move- 
ments. He  eats,  drinks,  smokes,  walks  about,  dresses  and 
undresses  himself,  rises  and  goes  to  bed  at  the  accus- 
tomed hours.  Nevertheless  pins  may  be  run  into  his 
body,  or  strong  electric  shocks  sent  through  it,  without 
causing  the  least  indication  of  pain ;  no  odorous  substance, 
pleasant  or  unpleasant,  makes  the  least  impression  ;  he 
eats  and  drinks  with  avidity  whatever  is  offered,  and 
takes  asaffX'tida  or  vinegar  or  quinine  as  readily  as  water; 
no  noise  affects  him ;  and  light  influences  him  only  under 
certain  conditions." 


44G  THE   PHYSICAL   BASIS   OF  MIND. 

Tliere  is  no  one  of  these  phenomena  that  is  unfamiliar 
to  students  of  mental  disease.  The  case  is  chiefly  re- 
markable from  the  periodicity  of  the  recurrence  of  the 
abnormal  state.  I  have  collected  other  cases  of  the  kind, 
and  may  hereafter  find  a  fitting  occasion  to  quote  them.* 
The  anaesthesia  and  "  unconsciousness  "  noted,  no  more 
prove  the  actions  performed  by  this  soldier  to  have  been 
purely  mechanical,  i.  e.  undetermined  by  sensation,  than 
anesthesia  and  unconsciousness  prove  somnambulists  and 
madmen  to  be  machines.  In  the  pathological  state  called 
"  ecstasy  "  there  is  a  considerable  diminution  of  sensibil- 
ity to  external  stimuli ;  with  a  concentration  on  certain 
feelings,  images,  trains  of  thought,  exhibiting  itself  in 
expressions  of  emotion.  "  Les  malades,"  says  a  master, 
"paraissent  entierement  absorbes  par  leurs  mouvements 
interieurs,  ils  refusent  generalement  de  manger,  et  spd- 
cialement  la  volonte  de  I'ame  semble  completement  en- 
chainee."  f 

86.  Observe  that  while  this  soldier  exhibits  such  in- 
sensibility to  certain  stimuli,  he  unequivocally  exhibits 
sensibility  to  other  stimuli.  All  his  acts  show  sense- 
guidance.  Sight  and  Touch  obviously  regulate  his  move- 
ments. And  when  he  feels  objects  placed  in  his  way, 
and  then  passes  beside  them,  wherein  does  this  differ 
from  the  normal  procedure  of  sensitive  organisms?  where- 
in does  it  resemble  automata  ?  Dr.  Mesmet —  from  whose 
narrative  the  case  is  cited  —  remarks  that  the  sense  of 
Touch  seems  to  persist  "  and  indeed  to  be  more  acute  and 
delicate  than  in  the  normal  state " ;  upon  which  Professor 
Huxley  has  this  comment :  —  "  Here  a  difficulty  arises. 
It  is  clear  from  the  facts  detailed  that  the  nervous  appa- 

*  Meanwhile  the  reader  is  referred  to  Schroder  tax  der  Kolk,  Pa- 
thologic der  Geisteskrankheitcn,  1863,  p.  51  ;  or  Jessen,  Physiologie  des 
raenschlichen  Berikcns,  1872,  p.  66. 

t  Geiesixgee,  Zes  Maladies  Mcntalcs,  p.  96. 


ANIMAL  AUTOMATISM,  447 

ratus  by  which  in  the  normal  state  sensations  of  touch 
are  excited  is  that  by  which  external  influences  determine 
the  movements  of  the  body  in  the  abnormal  state.  But 
does  the  state  of  consciousness,  which  we  term  a  tactile 
sensation,  accompany  the  operation  of  this  nervous  appa- 
ratus in  the  abnormal  state  ?  or  is  consciousness  utterly 
absent,  the  man  being  reduced  to  a  pure  mechanism  ?  It 
is  impossible  to  obtain  direct  evidence  in  favor  of  the  one 
conclusion  or  the  other ;  all  that  can  be  said  is  that  the 
case  of  the  frog  shows  that  the  man  may  be  devoid  of  any 
kind  of  consciousness." 

87.  It  is  here  we  are  made  vividly  aware  of  the  abso- 
lute need  there  is  to  disengage  the  terms  employed  from 
their  common  ambiguities.  All  the  evidence  of  a  tactile 
sensation  which  can  possibly  be  furnished,  on  the  objec- 
tive side,  is  furnished  by  the  actions  of  this  soldier ;  to 
doubt  it  would  be  to  throw  a  doubt  on  the  sensibility  of 
any  animal  unable  to  tell  us  what  it  felt ;  nay,  even  a 
man  if  he  were  dumb,  or  spoke  a  language  we  could  not 
understand,  could  give  us  no  other  proof.  We  conclude 
that  the  soldier  had  tactile  sensations,  because  we  see  him 
guided  by  them  as  we  ourselves  are  guided  by  tactile  sen- 
sations ;  we  know  that  he  is  an  organism,  not  a  machine,  and 
therefore  reject  the  inference  that  he  has  become  reduced 
to  a  "  pure  mechanism "  because  it  is  inferred  that  his 
consciousness  is  absent.  And  on  what  is  this  inference 
grounded  ?  1°,  The  belief  that  the  brain  is  the  sole  organ 
of  consciousness  (Sentience)  —  a  belief  flatly  disproved 
by  the  facts,  which  show  Sentience  when  the  brain  has 
been  removed;  and  2°,  the  belief  that  the  decapitated  frog, 
because  it  avoids  obstacles  and  redirects  its  leaps  to  avoid 
them,  does  so  without  Sentience.  According  to  the  defi- 
nition we  adopt,  we  may  either  say  that  the  decapitated 
frog,  and  the  soldier  in  his  abnormal  state,  act  without 
consciousness,  or  with  it.     l>ut  what  does  not  seem  per- 


448  THE  niYSiCAL  basis  of  mind. 

missible  is  to  deny  that  their  actions  exhibit  tlie  clearest 
evidence  of  scnsc-guidancc,  and  the  kind  oi'  volition  which 
this  sense-guidance  implies ;  and  this  is  quite  enough  to 
separate  them  from  actions  of  automata.  AVhen  a  man 
ducks  his  head  to  avoid  a  stone  which  he  sees  falling 
towards  him,  he  assuredly  has  a  sensation,  i.  e.  there  is  a 
grouping  of  neural  elements,  which  subjectively  is  a  sen- 
sation, and  this  originates  a  grouping  of  other  neural 
elements,  the  outcome  of  which  is  a  muscular  movement, 
which  subjectively  is  a  motor  sensation :  this  grouping 
would  not  have  been  originated  unless  the  particular 
grouping  had  preceded  it ;  nor  would  the  simple  retinal 
stimulus  have  excited  this  sensation  unless  the  nerv^e- 
centres  had  been  attuned  to  such  response  by  many  pre- 
vious experiences  :  the  ignorant  child  would  not  duck  its 
head  on  seeing  the  stone  approach.  In  our  familiar  use 
of  the  word  Consciousness  it  would  be  correct  to  say  that 
the  man  ducks  his  head  "  unconsciously " ;  and  yet  ex- 
pressing the  fact  in  psychological  language,  we  also  say : 
He  ducks  his  head  because  rcmemhering  the  pain  of 
former  similar  experiences,  he  knows  that  if  the  stone 
strikes  him  he  will  again  be  hurt  as  before,  therefore  he 
ivills  to  avoid  it ;  expressing  it  in  physiological  language 
we  may  say  :  The  man  acts  thus  because  he  is  so  organ- 
ized that  a  particular  neural  process  is  the  stimulus  of  a 
particular  central  discharge  ;  and  he  became  thus  organ- 
ized through  a  long  series  of  anterior  adjustments  re- 
sponding to  stimuli,  each  adjustment  being  the  activity 
of  the  vital  organism. 

88.  There  can  be  no  doubt  that  the  soldier  had  percep- 
tions, and  that  these  perceptions  guided  his  movements  ; 
whether  these  shall  be  called  "  states  of  conscious- 
ness" or  not,  is  a  question  of  terms.  Now  since  we  know 
that  certain  actions  arc  uniformbj  consequent  on  certain 
perceptions,  we  are  justified  in  inferring  that  ivhenever  the 


ANIMAL   AUTOMATISM.  449 

actions  are  performed,  the  2Jcrceptions  preceded  them  :  this 
inference  may  be  erroneous,  but  in  the  absence  of  positive 
evidence  to  the  contrary  it  is  that  which  claims  our  first 
assent.  Is  it  evidence  to  the  contrary  that  the  perception 
may  have  stimulated  the  action,  yet  been  unaccompanied 
by  the  special  mode  named  consciousness  ?  Not  in  the 
least.  We  learn  to  read  with  conscious  effort ;  each  letter 
has  to  be  apprehended  separately,  its  form  distinguished 
from  all  other  forms,  its  value  as  a  sign  definitely  fixed, 
yet  how  very  rarely  are  we  "  conscious  "  of  the  letters 
when  we  read  a  book  ?  Each  letter  is  perceived  ;  and  yet 
this  process  passes  so  rapidly  and  smoothly,  that  unless 
there  be  some  defect  in  a  letter,  or  the  word  be  mis- 
spelled, we  are  not  "  conscious  "  of  the  perceptions.  Are 
we  therefore  reading  automata  ?  * 

We  are  said  to  walk  unconsciously  at  times ;  and  the 
continuance  of  the  movement  is  said  to  be  due  to  reflex 
action.  But  it  is  demonstrable  that  the  cutaneous  sensi- 
bility of  the  soles  of  the  feet  is  a  primary  condition.  If 
the  skin  be  insensible,  the  walking  becomes  a  stumble. 
In  learning  to  walk,  or  dance,  the  child  fixes  his  eyes  on 
his  feet,  as  he  fixes  them  on  his  fingers  in  learning  to 
play  the  piano.  After  a  while  these  registered  sensations 
connected  with  the  muscular  sense  suffice  to  guide  his  feet 
or  his  fingers ;  but  not  if  feet  or  fingers  lose  their  sensi- 
bility. 

89.  Witli  these  explanations  let  us  follow  the  further 
details  of  this  soldier's  abnormal  actions : — 

*  M.  LuYs  cites  the  case  of  a  patient  who  conversed  quitj  rationally 
with  a  visitor  "sans  en  avoir  conscience,  et  ne  se  souvenait  de  ricn"  ; 
and  he  draws  the  extraordinary  conclusion  that  the  conversation  "s'ope- 
rait  en  vertu  des  fprces  reflexes."  —  Etudes  dc  Physiologic  ct  dc  Pathologic. 
Cerebralcs,  1874,  p.  117.  Is  it  not  obvious  that  the  patient  must  liave 
been  conscious  at  the  time,  though  the  consciousness  vanislied  like  that 
in  a  dream  ?  The  persistent  consciousness  is  the  continuous  linking  on 
of  one  state  with  previous  states  —  the  aji2)erception  of  tlie  past. 

c  c 


450  THE  PHYSICAL  BxVsis  of  mind. 

"The  mau  is  insensible  to  sensory  impressions  made 
through  the  ear,  the  nose,  the  tongue,  and,  to  a  great  ex- 
tent, the  eye ;  nor  is  he  susceptible  to  pain  from  causes 
operating  during  his  abnormal  state.  Nevertheless  it  is 
possible  so  to  act  upon  his  tactile  ajjjjaratus  as  to  give  rise 
to  those  molecular  changes  in  his  scnsorium  which  are  ordi- 
narily tJie  causes  of  associated  trains  of  ideas.  I  give  a 
striking  example  of  fliis  process  in  Dr.  Mesmet's  words : 
'  II  se  promenait  dans  le  jardin,  on  lui  remet  sa  canne 
qu'il  avait  laisse  tomber.  II  la  palpe,  promene  a  plu- 
sieurs  reprises  la  main  sur  la  poignee  coudee  de  sa 
canne  —  devient  attentif — semble  preter  Toreille  —  et 
tout  a  coup  appelle,  "  Henri !  les  voila  ! "  Et  alors  por- 
tant  la  main  derriere  son  dos  comme  pour  prendre  une 
cartouche,  il  fait  le  mouvement  de  charger  son  arme,  se 
couche  dans  I'lierbe  a  plat  ventre  dans  la  position  d'un 
tirailleur,  et  suit  avec  I'arme  epaulee  tons  les  mouve- 
ments  de  I'ennemi  qu'il  croit  voir  a  courte  distance.'  In 
a  subsequent  abnormal  period  Dr.  Mesmet  caused  the 
patient  to  repeat  this  scene  by  placing  him  in  the  same 
conditions.  Xow  in  this  case  the  question  arises  whether 
the  series  of  actions  constituting  this  singular  pantomime 
was  accompanied  by  the  ordinary  states  of  consciousness, 
the  appropriate  trains  of  ideas,  or  not?  Did  the  man 
dream  that  he  was  skirmishing  ?  or  was  he  in  the  con- 
dition of  one  of  Yaucanson's  automata  —  a  rnecJmnism 
vjorhecl  hy  molecular  changes  in  the  nervous  system  ?  Tlie 
analogy  of  the  frog  shows  that  the  latter  assumption  is 
perfectly  justifiable." 

90.  Before  criticising  this  conclusion  let  me  adduce 
other  illustrations  of  this  dreamlike  activity.  "A  gentle- 
man whom  I  attended  in  a  state  of  perfect  apoplexy," 
says  Abercrombie,  "  was  frequently  observ^ed  to  adjust  his 
nightcap  with  the  utmost  care  when  it  got  into  an  un- 
comfortable state:  first  pulling  it  down  over  his  eyes,  and 


ANIMAL   AUTOMATISM.  451 

then  turning  up  the  front  of  it  in  the  most  exact  man- 
ner." According  to  the  current  teaching,  these  actions, 
whicli  seem  like  evidence  of  sensation,  are  nothing  of  the 
kind,  because  —  the  patient  was  "  unconscious  "  ;  that  is 
to  say,  because  he  did  not  exhibit  one  complex  kind  of 
Sensibility,  it  is  denied  that  he  exhibited  another  kind ! 
he  did  not  feel  discomfort,  nor  feel  the  movements  by 
which  it  was  rectified  —  because  he  could  not  speak,  dis- 
cuss impersonal  questions,  nor  attend  to  what  was  said  to 
him  !  Abercrombie  cites  other  cases :  "  A  gentleman  who 
was  lying  in  a  state  of  'perfect  insensibility  from  disease  of 
the  brain  "  (note  the  phrase,  which  really  only  expresses 
the  fact  that  external  stimuli  did  not  create  their  normal 
reactions)  "  was  frequently  observed  even  the  day  before 
his  death  to  take  down  a  repeating  watch  from  a  little 
bag  at  the  head  of  his  bed,  put  it  close  to  his  ear  and 
make  it  strike  the  hour,  and  then  replace  it  in  the  bag 
with  the  greatest  precision.  Another  whom  I  saw  in  a 
state  of  profound  apoplexy,  from  which  he  recovered, 
liad  a  perfect  recollection  of  what  took  place  during  the 
attack,  and  mentioned  many  things  which  had  been  said 
in  his  hearing  when  he  was  supposed  to  be  in  a  state  of 
perfect  unconsciousness."  Dr.  Wigan  also  tells  of  a  lady 
A\hom  he  knew,  and  who  was  actually  put  in  a  coffin, 
under  the  belief  that  she  was  dead  when  in  a  trance. 
Her  sense  of  hearing  was  then  preternaturally  acute. 
Tn  her  second-floor  bedroom  she  heard  what  the  ser- 
vants said  in  her  kitchen.  When  lier  brotlicr  came  to 
see  her  and  he  declared  slie  should  not  be  buried  until 
putrefaction  set  in,  slie  felt  intense  gratitude  and  a  gush 
of  tenderness,  but  was  unable  to  move  even  an  eyelid  as 
a  manifestation  of  her  feeling.  Suddenly  all  her  faculties 
returned.  Dr.  Wigan  adds  that  he  visited  tlie  Countess 
Kscalante,  one  of  tlie  Spanish  refugees,  who  remained  in 
a  similar  state  for  a  short  period,  during  wliicli  slie  saw 


45'2  THE   niYSICAL   BASIS   OF   MIND. 

lici"  husliaiul  and  children,  and  was  quite  conscious  of  all 
they  did  and  said  — but  did  not  recognize  them  as  her 
own.  She  Mas  absolutely  without  the  power  of  moving 
a  finger  or  of  opening  her  mouth.  Dr.  Neil  Arnott  told 
me  of  a  similar  case  in  his  practice.  In  these  last  cases 
Ave  learn  that  consciousness  —  in  its  ordinary  accepta- 
tion—  was  present,  though  bystanders  could  see  no  trace 
of  it.  And  very  often  in  cases  where  Consciousness,  or 
at  any  rate  Sensibility,  is  clearly  manifested,  its  presence 
is  denied,  because  the  patient  on  recovering  his  normal 
condition  is  quite  unable  to  remember  anything  that  he 
felt  and  did.  Under  anffisthetics  patients  manifest  sensa- 
tion, but  on  awaking  they  declare  that  they  felt  nothing 
—  of  what  value  is  their  declaration  ?  M.  Despine  tells 
us  of  a  patient  who  under  chloroform  struggled,  swore, 
and  cried  out,  "  Mon  Dieu  !  queje  sovffrc  !  "  yet  when  the 
operation  was  over,  and  he  emerged  from  the  effects  of 
the  chloroform,  he  remembered  nothing  of  what  he  had 
felt.* 

91.  Eeturning  now  to  Dr.  Mesmet's  soldier,  and  to  the 
conclusion  that  his  dreamlike  acts  were  no  more  than  the 
actions  of  one  of  Vaucanson's  automata,  surely  we  are 
justified  in  concluding,  first,  that  these  actions  were  not 
of  the  same  kind  as  those  of  an  automaton,  since  they 
were  those  of  a  living  organism ;  secondly,  that  they  pre- 
sent all  the  evidence  positive  and  inferential  which  Sen- 
sibility can  present  in  the  actions  we  observe  in  another, 
and  do  not  feel  in  ourselves ;  and  thirdly,  if  with  physi- 
ologists we  agree  that  the  mechanism  of  these  actions  is 
"  worked  by  molecular  changes  in  the  nervous  system," 
there  is  some  difficulty  in  understanding  how  Conscious- 
ness, which  is  said  to  be  caused  by  such  changes,  could 

*  Abercrombie,  Inquiries  concerning  the  Intellectual  Powers,  1840, 
p.  151.  WiGAX,  The  Diuility  of  the  Mind,  1844,  p.  270.  Despine,  La 
Psychologic  Naturelle,  1868,  I.  54. 


ANIMAL   AUTOMATISM.  453 

have  been  absent  —  how  the  cause  could  operate  yet  no 
effect  he  lirodiiccd. 

92.  What  automata  can  be  made  to  perform  is  sur- 
prishig  enough,  but  they  can  never  be  made  to  display 
the  fluctuations  of  sense-guided  actions,  such  as  we  see  in 
the  report  of  Dr.  Mesmet's  soldier :  — 

"The  ex-sergeant  has  a  good  voice,  and  had  at  one  time 
been  employed  as  a  singer  at  a  cafe.  In  one  of  his  ab- 
normal states  he  was  observed  to  begin  humming  a  tune. 
He  then  went  to  his  room,  dressed  himself  carefully,  and 
took  up  some  parts  of  a  periodical  novel  which  lay  on  the 
bed,  as  if  he  were  trying  to  find  something.  Dr.  Mesmet, 
suspecting  that  he  was  seeking  his  music,  made  up  one 
of  these  into  a  roll  and  put  it  into  his  hand.  He  ap- 
2Jeared  satisfied,  took  up  his  cane,  and  went  down  stairs 
to  the  door.  Here  Dr.  Mesmet  turned  him  round,  and 
he  walked  quite  contentedly  in  the  opposite  direction. 
The  light  of  the  sun  shining  through  a  window  happened 
to  fall  upon  him,  and  seemed  to  suggest  the  footlights  of  the 
stage  on  which  he  was  accustomed  to  make  his  appear- 
ance. He  stopped,  opened  his  roll  of  imaginary  music, 
put  himself  in  the  attitude  of  a  singer,  and  sang  with 
perfect  execution  three  songs  one  after  the  other.  After 
which  he  wiped  his  face  with  his  handkerchief  and  drank 
without  a  grimace  a  tumbler  of  strong  vinegar-and-water." 

93.  Epileptic  patients  have  frequently  been  observed 
going  through  similar  dreamlike  actions  in  which  only 
those  external  stimuli  which  have  a  relation  to  the  dream 
seem  to  take  effect.*  We  interpret  these  as  phenomena 
of  disordered  mental  action,  the  burden  of  proof  lies  on 
liim  who  says  they  are  phenomena  of  pure  median  ism. 
A  mail-coach  does  not  suddenly  cease  to  be  a  mail-coach 

*  Dr.  HucnLiNGS  Jackson  has  quite  recently  cited  some  curious 
examples  in  his  own  practice.  See  West  Riding  Lunatic  Asylum  Re- 
ports  for  1875. 


454  THE  PHYSICAL   BASIS   OF  MIND. 

and  become  a  wlieelbarrow  because  the  coachman  is 
drunk,  or  lias  fallen  from  the  box.  The  horses,  no  longer 
guided  by  the  reins,  may  dash  off  the  highroad  into  gar- 
dens or  ditches ;  but  it  is  their  muscular  exertions  which 
still  move  the  coach. 

Can  any  one  conceive  an  automaton  acting  as  the  ser- 
geant is  described  to  be  in  the  following  passage  ?  — 

"  Sitting  at  a  table  he  took  up  a  pen,  felt  for  paper  and 
ink,  and  began  to  write  a  letter  to  his  general,  in  which 
he  recommended  liimself  for  a  medal  on  account  of  his 
good  conduct  and  courage.  It  occurred  to  Dr.  Mesmet  to 
ascertain  experimentally  how  far  vision  was  concerned 
in  this  act  of  writing.  He  therefore  interposed  a  screen  be- 
tween the  man's  eyes  and  his  hands ;  under  these  circum- 
stances he  ivcnt  on  tvriting  for  a  short  time,  hut  the  words  be- 
came illegible,  and  he  finally  stopped.  On  the  withdrawal 
of  the  screen,  he  began  to  write  again  where  he  had  left  off. 
The  substitution  of  water  for  ink  in  the  inkstand  had  a 
similar  result.  He  stopped,  looked  at  his  pen,  wiped  it  on 
his  coat,  dipped  it  in  the  water,  and  began  again,  with  the 
same  effect.  On  one  occasion  he  began  to  write  upon  the 
topmost  of  ten  superposed  sheets  of  paper.  After  he  had 
written  a  line  or  two,  this  sheet  was  suddenly  drawn 
away.  Thej^e  ivas  a  slight  expression  of  surprise,  but  he 
continued  his  letter  on  the  second  sheet  exactly  as  if  it 
had  been  the  first.  This  operation  was  repeated  five 
times,  so  that  the  fifth  sheet  contained  nothing  but  the 
writer's  signature  at  the  bottom  of  the  page.  Neverthe- 
less, when  the  signature  was  finished,  his  eyes  turned  to 
the  top  of  the  blank  sheet,  and  he  went  through  the  form 
of  reading  over  what  he  had  written,  a  movement  of  the 
lips  accompanying  each  word ;  moreover,  with  his  pen  he 
put  in  such  corrections  as  were  needed" 

94.  Dr.  Mesmet  concludes  that  "  his  patient  sees  some 
things  and  not  others ;  that  the  sense  of  sight  is  accessible 


ANIMAL  AUTOMATISM.  455 

to  all  things  which  are  brought  into  relation  with  him  by 
the  sense  of  touch,  and,  on  the  contrary,  is  insensible 
to  things  which  lie  outside  this  relation."  In  other 
words,  the  sensitive  mechanism  acts,  but  acts  abnormally. 
This  is  precisely  what  is  observed  in  somnambulists.  Yet 
Professor  Huxley,  who  makes  the  comparison,  appears  to 
regard  both  states  as  those  in  which  the  organism  is  re- 
duced to  a  mere  mechanism,  because  on  recovering  tlieir 
normal  state  the  patients  are  unconscious  of  what  has 
passed ;  and  because  the  frog,  without  its  brain,  also  mani- 
fests analogous  phenomena.  Neither  premise  warrants 
the  conclusion.  I  have  already  touched  on  the  uncon- 
sciousness of  past  actions ;  let  me  add  the  case  of  Faraday, 
who  w^as  assuredly  not  an  automaton  when  he  prepared 
and  delivered  a  course  of  lectures  which  were  neverthe- 
less so  entirely  obliterated  from  his  memory  that  the  next 
year  he  prepared  and  delivered  the  same  course  once  more, 
without  a  suspicion  that  it  was  not  a  new  one.  As  to 
the  frog,  I  must  leave  that  case  till  I  come  to  examine  the 
evidence  on  which  the  hypothesis  of  the  purely  mechani- 
cal nature  of  spinal  action  rests. 

95.  The  point  never  to  be  left  out  of  sight  is  that 
actions  which  are  known  to  be  preceded  and  accompanied 
by  sensations  do  not  lose  their  special  character  of  Sen- 
tience, as  actions  of  a  sentient  mechanism,  because  they  are 
not  also  preceded  and  accompanied  by  that  peculiar  state 
which  is  specially  called  Consciousness,  i.  e.  attention  to 
the  passing  changes  (comp.  p.  403).  When  we  see  a  man 
playing  the  piano,  and  at  the  same  time  talking  of  some- 
thing far  removed  from  the  music,  we  say  his  fingcre 
move  unconsciously;  but  we  do  not  conclude  that  he  is  a 
musical  machine  —  muscular  sensations  and  musical  sen- 
sations regulate  every  movement  of  his  fingers ;  and  if  he 
strikes  a  false  note,  or  if  one  of  the  notes  jangles,  he  is 
instantly  conscious  of  the  fact     Either  we  must  admit 


456  THE  niYSicAL  basis  of  mind. 

that  his  brain  is  an  essential  part  of  the  mechauisni  by 
which  the  piano  was  played,  and  its  function  an  essential 
agent  in  the  playing ;  or  else  we  must  admit  that  the 
brain  and  its  function  M'ere  not  essential,  and  therefore 
the  playing  would  continue  if  the  brain  were  removed. 
In  the  latter  case,  we  should  have  a  musical  automaton. 
That  a  particular  group  of  sensations,  such  as  musical 
tones,  will  set  going  a  particular  group  of  muscular  move- 
ments, without  the  intervention  of  any  conscious  effort,  is 
not  more  to  be  interpreted  on  purely  mechanical  prin- 
ciples, than  that  a  particular  phrase  will  cause  a  story- 
teller to  repeat  a  familiar  anecdote,  or  an  old  soldier  "  to 
fight  his  battles  o'er  again." 

9G.  Let  us  now  pass  to  another  consideration,  namely, 
whether  Consciousness  —  however  interpreted  —  is  legiti- 
mately conceived  as  a  factor  in  the  so-called  conscious 
and  voluntary  actions ;  or  is  merely  a  collateral  result  of 
certain  organic  activities  ?  To  answer  this,  we  must  first 
remember  that  Consciousness  is  a  purely  subjective  pro- 
cess ;  although  we  may  believe  it  to  be  objectively  a  neural 
process,  we  are  nevertheless  passing  out  of  the  region  of 
Physiology  when  we  speak  of  Feeling  determining  Action. 
Motion  may  determine  Motion ;  but  Feeling  can  only 
determine  Feeling.  Yet  we  do  so  speak,  and  are  justified. 
For  thereby  we  implicitly  declare,  what  Psychology  ex- 
plicitly teaches,  namely,  that  these  two  widely  different 
aspects,  objective  and  subjective,  are  but  the  two  faces  of 
one  and  the  same  reality.  It  is  thus  indifferent  whether 
we  say  a  sensation  is  a  neural  process,  or  a  mental  process  : 
a  molecular  change  in  the  nervous  system,  or  a  change  in 
Feeling.  It  is  either,  and  it  is  both,  as  I  have  elsewhere 
explained.*  There  it  was  argued  that  the  current  hypoth- 
esis of  a  neural  process  causing  the  mental  process  — 
molecular  movement  being  in  some  mysterious  way  trans- 

*  Problems,  Vol.  II.  p.  478,  sq. 


ANIMAL  AUTOMATISM.  457 

formed  into  sensatioij  —  is  not  only  inconceivable,  but 
altogether  unnecessary ;  Avhereas  the  hypothesis  that  the 
two  aspects  of  the  one  phenomenon  are  simply  two  differ- 
ent expressions,  now  in  terms  of  Matter  and  Motion,  and 
now  in  terms  of  Consciousness,  is  in  harmony  with  all 
the  inductive  evidence. 

97.  "It  may  be  assumed,"  says  Professor  Huxley,  "that 
molecular  changes  in  the  brain  are  the  causes  of  all  the 
states  of  consciousness  of  brutes.  Is  there  any  evidence 
that  these  states  of  consciousness  may  conversely  cause 
those  molecular  changes  which  give  rise  to  muscular 
motion  ?  I  see  no  such  evidence.  The  frog  walks,  hops, 
swims,  and  goes  through  his  gymnastic  performances, 
quite  as  well  without  consciousness,  and  consequently 
without  volition,  as  with  it ;  and  if  a  frog  in  his  natural 
state  possesses  anything  corresponding  with  what  we  call 
volition,  there  is  no  reason  to  think  that  it  is  anytliing  hut 
a  concomitant  of  the  molecular  changes  in  the  train,  which 
form  2jart  of  the  series  involved  in  the  production  of  motion. 
The  consciousness  of  brutes  would  appear  to  be  related 
to  the  mechanism  of  their  body  simply  as  a  collateral 
product  of  its  working,  and  to  be  as  completely  ivithout  any 
power  of  modifying  that  working  as  the  steam-whistle  which 
accompanies  the  vjorh  of  a  locomotive  engine  is  without  in- 
Jluence  upon  its  r^iaehinery.  Their  volition,  if  they  have 
any,  is  an  emotion  indicative  of  physical  changes,  not  a 
cause  of  such  changes."  Particular  attention  is  called  to 
the  passages  in  italics.  In  the  first  is  expressed  a  view 
which  seems  not  unlike  the  one  I  am  advocating,  but 
wliich  is  contradicted  by  the  second.  Let  us  consider 
what  is  implied. 

93.  When  Consciousness  is  regarded  solely  under  its 
subjective  aspect  there  is  obviously  no  place  for  it  among 
material  agencies,  regarded  as  objective.  So  long  as  we 
have  the  material  mechanism  in  view  we  have  nothing 

VOL.  III.  20 


458  THE  PHYSICAL  BASIS   OF   MIND. 

but  material  changes.  This  applies  to  the  frog,  with  or 
without  its  brain ;  to  man,  supposed  to  be  moved  by  voli- 
tion, or  supposed  to  move  automatically.  The  introduc- 
tion of  Consciousness  is  not  the  introduction  of  another 
agent  in  the  series,  but  of  a  new  aspect ;  the  neural 
process  drops  out  of  sight,  the  mental  process  replaces  it. 
The  question  whether  we  have  any  ground  for  inferring 
that  in  the  series  there  is  included  the  particular  neural 
state  which  subjectively  is  a  state  of  Consciousness,  must 
be  answered  according  to  the  evidence.  Well,  the  evi- 
dence shows  that  the  actions  do  involve  the  co-operation ; 
and  this  Professor  Huxley  expresses  when  he  says  that  the 
molecular  changes  in  the  brain  form  part  of  the  series  in- 
volved in  the  production  of  motion.  Whether  we  regard 
the  process  objectively  as  a  series  of  molecular  changes, 
or  subjectively  as  a  succession  of  sentient  changes,  the 
sum  of  which  is  on  the  one  side  a  motor  impulse,  on  the 
other  a  state  of  consciousness,  we  must  declare  Conscious- 
ness to  be  an  agent,  in  the  same  sense  that  we  declare  one 
clmngc  in  the  organism  to  he  an  agent  in  some  other  change. 
The  facts  are  the  same,  whether  w^e  express  them  in 
physiological  or  in  psychological  terms.  The  physiolo- 
gist, having  only  the  material  aspect  of  the  organism  in 
view,  says,  "A  cerebral  process  initiates  a  motor  process  " ; 
the  psychologist  says,  "A  sensation  determines  an  action." 
Unless  the  two  processes  have  been  linked  together  by 
an  organic  disposition,  native  or  acquired,  there  will  be  no 
such  motor  process  following  the  cerebral  process.  A  dog 
standing  outside  the  gate  is  unable  to  ring  the  bell,  though 
having  seen  anotlier  dog  ring  it,  he  may  wish  to  do  so ; 
but  the  cerebral  process  (his  wish)  is  not  linked  on  to  the 
needful  motor  process  —  he  has  not  learned  to  realize 
the  wish ;  whereas  the  other  dog,  having  by  trial  hit  upon 
the  right  mode  of  directing  his  muscles,  has  registered  this 
experience,  and  can  ring  the  bell.     The  organized  disposi- 


ANIMAL  AUTOMATISM.  459 

tion  which  enables  the  dog  to  do  this  may  truly  enough 
he  called  a  modification  of  the  mechanism ;  but  what  we 
have  here  to  note  is  that  a  sensation  originally  determined 
the  movement,  and  always  determines  it. 

99.  It  is  the  unfortunate  ambiguity  of  the  word  Con- 
sciousness, and  tlie  questionable  hypothesis  of  the  brain 
being  the  sole  seat  of  Sensibility,  which  darken  this  in- 
vestigation. Because  animals,  after  the  brain  has  been 
removed,  are  seen  to  perform  certain  actions  as  deftly  as 
before,  they  are  said  to  perform  these  without  the  inter- 
vention of  Consciousness  ;  when  all  that  is  jDroved  by  the 
facts  is  that  these  actions  are  performed  without  the  in- 
tervention of  the  brain.  In  support  of  this  explanation, 
examples  are  cited  of  unconscious  actions  performed  by 
human  beings.  But  if  we  assign  Sensibility  not  to  one 
part  of  the  nervous  system  exclusively,  but  to  the  whole, 
we  can  readily  understand  how  the  loss  of  a  part  will 
be  manifested  by  very  marked  changes  in  the  reactions 
of  the  whole,  and  yet  not  altogether  prevent  the  reactions 
of  the  parts  remaining  intact.  An  animal  must  respond 
somewhat  differently  with  and  without  a  brain.  One 
marked  difference  is  the  spontaneity  of  the  actions  when 
the  brain  is  intact,  and  the  loss  of  much  spontaneity 
when  the  brain  is  injured  or  removed.  Cerebral  processes 
prompt  and  regulate  actions,  as  the  pressure  of  the  driver 
on  the  reins  prompts  and  regulates  the  movements  of  the 
horses ;  but  the  carriage  is  moved  by  tlie  horses  and  not 
by  the  driver ;  and  the  action  is  executed  by  the  motor 
mechanism,  whether  the  incitation  arise  in  a  cerebral 
process  or  a  peripheral  stimulation. 

100.  If  we  admit  that  Consciousness  is  itself  an  organic 
process,  accompanying  the  molecular  changes  as  a  convex 
surface  accompanies  a  concave,  we  must  also  admit  that 
its  fluctuations  are  adjustments  and  readjustments  of  the 
organic  mcclianisin,  and  that  the  actions  arc  tlic  (sffects 


460  THE   PHYSICAL   BASIS   OF   MIND. 

of  these  —  tlieir  resultants.  The  loss  of  the  brain  must 
obviously  cause  a  great  disturbance  in  these  adjustments. 
We  may  call  that  a  loss  of  Consciousness,  if  we  clioose 
to  limit  the  term  to  one  mode  of  sentient  reaction.  But 
this  loss  of  a  mode  does  not  change  those  reactions  which 
persist  so  as  to  convert  them  into  purely  mechanical  re- 
actions. A  troop  of  soldiers  may  have  lost  its  directing 
officer,  but  will  fight  with  the  old  weapons  and  the  old 
intelligence,  though  not  with  the  same  convergence  of 
individual  efforts.  A  frog  or  a  pigeon  no  more  acts  as 
tvcll  without  a  brain  as  with  a  brain,  than  the  troop  of 
soldiers  fights  as  well  without  an  officer. 

101.  Having  thus  claimed  a  place  for  Consciousness  in 
the  series  of  organic  processes,  let  us  now  see  whether 
it  has  a  place  among  the  active  agencies.  According  to 
Professor  Huxley  it  is  not  itself  an  agent,  but  only  the 
"  collateral  product  of  the  working  of  the  machine."  It 
accompanies  actions,  it  does  not  direct  them.  It  is  an 
index,  not  a  cause. 

Surely  it  seems  more  accurate  to  say  that  it  accompa- 
nies and  directs  the  working  ?  It  accompanies  the  work- 
ing in  two  senses :  first,  as  the  subjective  aspect  of  the 
objective  process ;  secondly,  as  the  change  which  pro- 
duces a  subsequent  change,  that  is  to  say,  the  movements 
initiated  by  a  feeling  are  themselves  also  felt  as  they  pass ; 
and  this  feeling  enters  into  the  general  stream  of  simulta- 
neous excitations  out  of  which  new  movements  and  feel- 
ings arise;  or  to  express  it  physiologically,  the  sensory 
impressions  determine  muscular  movements,  which  in 
turn  react  on  the  nerve-centres,  and  these  reactions  blend 
with  the  general  excitation  of  reflected  and  re-reflected 
processes.*     Since  every  change   in  Consciousness  is  a 

*  "Le  sentiment  fait  naitre  le  mouvement,  et  le  mouvement  donne 
naissance  au  sentiment."  —  Van  Deen,  Traites  et  Decouvcrtes  sur  la 
Moelle  Spinier e,  1841,  p.  102, 


ANIMAL  AUTOMATISM.  461 

change  in  the  sentient  organism,  which  objectively  is 
a  change  in  the  nervous  centres,  the  working  of  the 
mechanism  being  itself  a  dependent  series  of  such  changes, 
each  movement  must  have  a  reflected  influence  on  the 
general  state.  This  reflected  influence  may  be  viewed  as 
a  collateral  product  of  the  working ;  but  there  is  no  real 
analogy  between  it  and  the  whistle  of  the  steam-engine, 
because  this  reflected  influence  demonstrably  docs  inter- 
vene in  the  subsequent  movements.  The  feeling  which 
accompanies  or  follows  a  particular  movement  cannot 
indeed  modify  J7ia^  movement,  since  that  is  already  set 
going,  or  has  passed ;  here  there  is  some  analogy  to  the 
steam- whistle ;  but  the  analogy  fails  in  the  subsequent 
history :  no  movements  whatever  of  the  steam-engine  are 
modified  by  the  whistle  which  accompanies  the  working 
of  that  engine ;  yet  how  the  reflected  influence  modifies 
the  working  of  the  organism !  If  the  hand  be  passing 
over  a  surface,  there  is,  accompanying  this  movement,  a 
succession  of  muscular  and  tactile  feelings  which  may  be 
said  to  be  collateral  products.  But  the  feeling  which  ac- 
comjoanics  one  muscular  contraction  is  itself  the  stimulus  of 
the  next  contraction ;  if  anywhere  during  the  passage  the 
hand  comes  upon  a  spot  on  the  surface  which  is  wet  or 
rough,  the  change  in  feeling  thus  produced,  although  a  col- 
lateral product  of  tlie  movement,  instantly  changes  the  di- 
rection of  the  hand,  suspends  or  alters  the  course — that  is 
to  say,  the  collateral  product  of  one  movement  becomes  a  di- 
recting factor  in  the  succeeding  movement.  Now  this  is  pre- 
cisely what  no  automaton  can  effect,  unless  for  changes 
that  are  prearranged.  A  steam-engine  drives  its  locomo- 
tive over  the  rails,  be  they  smooth  or  rough,  entire  or 
broken ;  it  whistles  as  it  goes,  but  no  whistling  directs 
and  redirects  its  path. 

102.   Volition  is  said  to  be  an  "  emotion  indicative  of 
physical  changes,  not  a  cause  of  such  changes."     Here  it 


462  THE   PHYSICAL  BASIS  OF  MIND. 

is  necessary  to  understand  in  what  sense  the  term  cause 
is  employed.  I  should  prefer  stating  the  proposition 
thus:  a  volition  is  a  state  of  the  sentient  organism,  indic- 
ative of  physical  changes  which  have  taken  place,  and 
of  changes  which  will  take  place.  Because  it  is  the  ex- 
pression of  the  first  group  of  changes,  it  cannot  be  their 
origin;  but  it  can  be,  and  is  the  origin  of  the  second 
group,  which  it  initiates.  The  indignation  excited  by  an 
insult  or  a  blow  is  not  the  origin  of  the  emotion  or  the 
pain,  but  it  is  the  origin  of  the  actions  which  are  prompted 
by  this  sentient  state.  In  fact  no  sooner  do  we  admit 
that  the  organism  is  a  sentient  mechanism,  than  the  con- 
clusion is  irresistible  that  Sensibility  is  a  factor  in  the 
working  of  that  mechanism. 

103.  "  Much  ingenious  argument,"  says  Professor  Hux- 
ley, "  has  at  various  times  been  bestowed  upon  the  ques- 
tion :  How  is  it  possible  to  imagine  that  volition  which 
is  a  state  of  consciousness,  and  as  such  has  not  the  slight- 
est community  of  nature  with  matter  and  motion,  can 
act  upon  the  moving  matter  of  which  the  body  is  com- 
posed, as  it  is  assumed  to  do  in  voluntary  acts  ?  But  if, 
as  is  here  suggested,  the  voluntary  acts  of  brutes  —  or 
in  other  words,  the  acts  which  they  desire  to  perform  — 
are  as  purely  mechanical  as  the  rest  of  their  actions,  and 
are  simply  accompanied  by  the  state  of  consciousness 
called  volition,  the  inquiry,  so  far  as  they  are  concerned, 
becomes  superfluous.     Their  volitions  do  not  enter  into 

the  chain  of  causation  of  their  actions  at  all As 

consciousness  is  brought  into  existence  only  as  the  con- 
sequence of  molecular  motion  in  the  brain,  it  follows  that 
it  is  an  indirect  product  of  material  changes.  The  soul 
stands  related  to  the  body  as  the  bell  of  a  clock  to  the 
works,  and  consciousness  answers  to  the  sound  wdiicli  the 
bell  gives  out  when  it  is  struck."  This  has  been  answered 
in  the  foregoing  pages ;  nor  do  I  think  the  reader  who 


ANIMAL   AUTOMATISM.  463 

has  recognized  the  ambiguity  of  the  term  Consciousness, 
and  the  desirability  of  replacing  it  in  this  discussion  by 
the  less  equivocal  term  Sentience,  will  need  more  to  be 
said. 

104.  The  important  question  whether  reflex  actions  are 
insentient,  and  therefore  mechanical,  will  occupy  us  in  the 
next  problem.  The  question  of  Automatism  which  has 
been  argued  in  the  preceding  chapters,  may,  I  think,  be 
summarily  disposed  of  by  a  reference  to  the  irresistible 
evidence  each  man  carries  in  his  own  consciousness  that 
his  actions  are  frequently  —  even  if  not  always  —  deter- 
mined by  feelings.  He  is  quite  certain  that  he  is  not  an 
automaton,  and  that  his  feelings  are  not  simply  collateral 
products  of  his  actions,  without  the  power  of  modifying 
and  originating  them.  Now  this  fundamental  fact  cannot 
be  displaced  by  any  theoretical  explanation  of  its  factors. 
Nor  would  this  fundamental  truth  be  rendered  doubtful, 
even  supposing  we  were  to  grant  to  the  full  all  that  is 
adduced  as  evidence  that  some  actions  were  the  result  of 
purely  mechanical  processes  without  sentience  at  all.  I 
am  a  conscious  organism,  even  if  it  be  true  that  I  some- 
times act  unconsciously.  I  am  not  a  machine,  even  if  it 
Ije  true  that  I  sometimes  act  mechanically. 


PROBLEM    IV. 


THE  REFLEX   THEORY, 


"Si  onmes  patres  sic,  at  Ego  non  sic." -  Abelard,  Sic  et  Kon. 

"  Will  man  bestimmen  wo  der  Mechanismus  auflidrt  und  wo  der  Wille 
anfiingt  so  ist  die  Frage  iiberhaupt  falscli  gestellt.  Dean  mau  setzt  liier  Be- 
griffe  einander  gegeniiber  die  gar  keine  Gegensatze  sind.  Vorgebildet  iu  den 
mechanischen  Bedingungen  des  Nervensystems  sind  alle  Bewegungen."  — 
WuNDT,  Physiologische  Psychologie. 

"  SoUte  die  so  durchsiclitige  Homologie  zwischen  Him  iind  Riickenmark, 
wie  solche  sich  schlagend  in  Ban  und  Entwicklung  dartbut,  wesentlich  andere 
physiologiscbe  Qualitaten  bedingen?"  —  Luschinger  in  Pfluger's  Archiv, 
Bd.  XIV.  384. 


20* 


THE  REFLEX   THEORY. 


CHAPTEE    I. 

THE   PROBLEM   STATED. 

1.  The  peculiarity  of  the  Eeflex  Theory  is  its  exclusion 
of  Sensibility  from  the  actions  classed  as  reflex ;  in  conse- 
quence of  which,  the  actions  are  considered  to  be  "  purely 
mechanical." 

No  one  denies  that  most  of  the  reflex  actions  often 
have  conscious  sensations  preceding  and  accompanying 
them,  but  these  are  said  not  to  be  essential  to  the  per- 
formance of  the  actions,  because  they  may  be  absent  and 
the  actions  still  take  place.  It  is  notorious  that  we 
breathe,  wink,  swallow^  etc.,  whether  we  are  conscious  of 
tliese  actions  or  not.  Our  conclusion  therefore  is  that 
these  jjeculiar  states  of  Consciousness  are  accessory,  not 
essential  to  the  performance  of  these  actions.  The  fact  is 
patent,  the  conclusion  irresistible.  But  now  consider  the 
equivoque :  because  an  action  takes  place  without  our 
being  conscious  of  it,  the  action  is  said  to  have  had  no 
sensation  determining  it.  This,  which  is  a  truism  when 
we  limit  Consciousness  to  one  of  the  special  modes  of 
Sensibility,  or  limit  sensation  to  this  limited  Conscious- 
ness, is  a  falsism  when  we  accept  Consciousness  as  the 
total  of  all  combined  sensibilities,  or  Sensation  as  the 
reaction  of  tlie  sensory  mechanism.  That  a  reflex  action 
is  determined  by  the  sensory  mechanism,  no  one  disputes ; 


468  THE  PHYSICAL  BASIS   OF   MIND. 

whether  the  reaction  of  a  sensory  mechanism  shall  be 
called  a  sensation  or  not,  is  a  question  of  terms.  I  have 
shown  why  it  must  be  so  called  if  anything  like  coherence 
is  to  be  preserved  in  physiological  investigations  ;  and  I 
have  more  than  once  suggested  that  the  fact  of  intellectual 
processes  taking  place  at  times  with  no  more  conscious- 
ness than  reflex  actions,  is  itself  sufficient  to  show  that  a 
process  does  not  lapse  from  the  mental  to  the  mechanical 
sphere  simply  by  passing  unconsciously. 

Inasmuch  as  an  organism  is  a  complex  of  organs,  its 
total  function  must  be  a  complex  of  particular  functions, 
each  of  which  may  analytically  be  treated  apart.  Vitality 
is  the  total  of  all  its  physiological  functions,  and  Con- 
sciousness the  total  of  all  its  psychological  functions. 
But  inasmuch  as  it  is  only  in  its  relation  to  the  whole 
that  each  part  has  functional  significance,  and  cannot 
therefore  be  isolated  in  reality,  as  it  is  in  theory  —  can- 
not live  by  itself,  act  by  itself,  independently  of  the  organ- 
ism of  which  it  is  an  organ,  there  is  strict  accuracy  in 
saying  that  no  particular  sensation  can  exist  without  in- 
volving Consciousness  ;  for  this  is  only  saying  that  no 
sensory  organ  can  react  without  at  the  same  time  involv- 
ing a  reaction  of  the  general  sensorium.  But  since  this 
general  sensorium  is  simultaneously  affected  by  various 
excitations  each  of  which  is  a  force,  every  sensation, 
perception,  emotion,  or  volition  is  a  resultant  of  the  com- 
position of  these  forces ;  and  as  there  can  be  only  one 
resultant  at  a  time,  to  be  replaced  by  another  in  swift 
succession,  this  one  represents  the  state  of  Consciousness, 
and  this  state  may  or  may  not  be  felt  under  the  peculiar 
mode  named  "  Consciousness,"  in  its  special  meaning.  In 
other  words,  the  reaction  of  a  sensory  organ  is  ahvays  sen- 
tient, but  not  always  consentient. 

2.  Let  us  illustrate  this  by  the  sensation  of  musical 
tone.     When  we  hear  a  tone  we  are  affected  not  only  by 


THE   EEFLEX   THEORY.  469 

the  fundamental  tone,  representing  the  vibrations  of  the 
sounding  body  as  a  whole,  but  also  by  the  harmonics  or 
overtones,  representing  the  vibrations  of  the  several  parts 
of  that  whole.  It  is  these  latter  vibrations  which  give 
the  tone  its  timbre,  or  peculiar  quality ;  and  as  the  har- 
monics are  variable  with  the  variable  structure  of  the 
vibrating  parts,  two  bodies  which  have  the  same  fun- 
damental tone  may  have  markedly  different  qualities. 
There  are  some  tones  wliich  are  almost  entirely  free  from 
harmonics  ;  that  is  to  say,  their  harmonics  are  too  faint 
for  our  ear  to  appreciate  them,  though  we  know  that  the 
vibrations  must  be  present.  Apply  this  to  the  excitations 
of  the  sensorium.  Each  excitation  will  have  its  funda- 
mental feeling,  and  more  or  less  accompanying  thrills  of 
other  feelings  :  it  is  these  thrills  which  are  the  harmonics, 
giving  to  each  excitation  its  specific  quality;  but  they 
may  be  so  faint  that  no  specific  quality  is  discriminated. 
A  fly  settles  on  your  hand  while  you  are  writing,  the  faint 
thrill  which  accompanies  this  excitation  of  your  sensory 
nerve  gives  the  specific  sensation  of  tickling,  and  tliis 
causes  you  to  move  your  hand  with  a  jerk.  If  your  atten- 
tion is  preoccupied,  you  are  said  to  be  unconscious  of  the 
sensation,  and  the  jerk  of  your  hand  is  called  a  reflex 
action  ;  but  if  your  attention  is  not  preoccupied,  or  if  the 
thrill  is  vivid,  you  are  said  to  be  conscious  of  the  sensa- 
tion, and  the  action  is  no  longer  reflex,  but  volitional. 
Obviously  here  tlie  difference  depends  not  on  the  sentient 
excitation  by  an  impression  on  the  nerve,  but  on  tlie  state 
of  the  general  sensorium  and  its  consequent  reaction. 
Had  not  the  impression  lieen  carried  to  tlie  sensorium,  no 
movement  would  have  followed  the  fly's  alighting  on  your 
hand,  because  no  sen-sation  (sensory  reaction)  would  have 
been  excited;  the  hypothesis  of  a  purely  mechanical  re- 
llcx  is  quite  inadmissiljle. 

3.    Or  take  another  case.     It  sometimes  happens  that 


470  THE  PHYSICAL  basis  of  mind. 

we  fall  asleep  while  some  one  is  reading  to  us  aloud.  The 
sounds  of  the  reader's  voice  at  first  awaken  the  familiar 
thrills  whicli  give  the  tones  their  quality,  and  the  words 
their  significance ;  but  gradually  as  sleep  steals  over  us, 
the  organism  ceases  to  react  thus ;  the  words  lose  more 
and  more  of  their  significance,  the  tones  lose  more  and 
more  of  their  harmonics ;  at  last  we  pass  into  the  state 
of  unconsciousness  —  we  cease  to  hear  what  is  read.  But 
do  we  cease  to  feel  ?  AVe  have  not  heard,  but  we  have 
been  affected  by  the  sounds.  Not  by  distinguishable  sen- 
sations ;  nevertheless  a  state  of  the  general  Sensibility 
has  been  induced.  To  prove  that  we  have  been  affected 
is  easy.  Let  the  reader  suddenly  cease,  and  if  our  sleep 
be  not  too  profound,  we  at  once  awake.  Now,  unless  the 
sound  of  his  voice  had  affected  us,  it  is  clear  that  the  ces- 
sation of  that  could  not  have  affected  us.  Or  let  us  sup- 
pose our  sleep  to  be  unbroken  by  the  cessation  of  the 
sound ;  even  this  will  not  prove  that  we  have  been  unaf- 
fected by  the  sounds,  it  will  merely  prove  that  those 
sounds,  or  their  cessation,  did  not  excite  a  conscious  state. 
For  let  the  reader,  in  no  louder  tone,  ask,  "Are  you 
asleep?"  and  we  start  up,  with  round  eyes,  declaring, 
"Not  at  all."  Nay,  should  even  this  question  fail  to 
awaken  us,  the  speaker  need  only  utter  some  phrase  likely 
to  excite  a  thrill  —  such  as,  "  There 's  the  postman  !  "  or, 
"  I  smell  fire  ! "  and  we  start  up. 

I  remember  once  trying  the  experiment  on  a  wearied 
waiter,  who  had  fallen  asleep  in  one  of  the  unoccupied 
boxes  of  a  tavern.  His  arm  rested  on  the  table,  and  his 
head  rested  on  his  arm :  he  snored  the  snore  of  the  weary, 
in  spite  of  tlie  noisy  laughter  and  talk  of  the  guests.  I 
called  out  "  Johnson,"  in  a  loud  tone.  It  never  moved 
him.  I  then  called  "Wilson,"  but  he  snored  on.  No 
sooner  did  I  call  "  waiter,"  than  he  raised  his  head  with  a 
sleepy  "  yessir."     Now,  to  suppose,  in  this  case,  that  he 


THE   REFLEX   THEORY.  471 

had  no  sensation  when  the  words  "  Johnson  "  and  "  Wil- 
son "  reached  his  ears,  but  had  a  sensation  when  the  word 
"  waiter "  reached  his  ears,  is  to  suppose  that  two  similar 
causes  will  not  produce  a  similar  effect.  The  dissyllable 
"  Johnson  "  would  excite  as  potent  a  reaction  of  his  sen- 
sory organ  as  the  dissyllable  "  waiter  "  ;  but  the  thrills  — 
the  reflex  feelings  —  were  different,  because  tlie  word 
"  Johnson  "  was  not  associated  in  his  mind  with  any  defi- 
nite actions,  whereas  the  word  "  waiter  "  was  so  associated 
as  to  become  an  automatic  impulse.* 

4.  Two  sisters  are  asleep  in  the  same  bed,  and  a  child 
cries  in  the  next  room.  The  sounds  of  these  cries  will 
give  a  similar  stimulus  to  the  auditory  nerve  of  each  sis- 
ter, and  excite  a  similar  sensory  reaction  in  each.  Never- 
theless, the  one  sister  sleeps  on  undisturbed,  and  is"  said 
not  to  hear  the  cry.  The  other  springs  out  of  bed,  and 
attends  to  the  child,  because  she  being  accustomed  to 
attend  on  tlie  cliild  and  soothe  it  when  crying,  the  pri- 
mary sensation  has  excited  secondary  sensations,  thrills 
which  lead  to  accustomed  actions.  Could  we  look  into 
the  mind  of  the  sleeping  sister,  we  should  doubtless  find 
that  the  sensation  excited  by  the  child's  cry  had  merged 
itself  in  the  general  stream,  and  perhaps  modified  her 
dreams.  Let  her  become  a  mother,  or  take  on  the  tender 
duties  of  a  mother,  and  her  vigilance  will  equal  that  of 
her  sister ;  because  the  cry  will  then  excite  a  definite 
reflex  feeling,  and  a  definite  course  of  action.  But  this 
very  sister,  who  is  so  sensitive  to  the  cry  of  a  child,  will 
be  undisturbed  by  a  much  louder  noise ;  a  dog  may  bark, 
or  a  heavy  wagon  thunder  along  the  street,  without  caus- 
ing her  to  turn  in  bed.f 

*  Dr.  Cakpkntkr  tells  a  similar  story  of  Admiral  Codiunoton,  who, 
wliPii  a  midshipman,  could  always  be  awakened  from  the  profoundest 
slumber  if  the  word  "signal"  were  uttered  ;  whereas  no  other  word  dis- 
turbed him. 

t  C'ompare  an  intere.sting  personal  example  given  by  Joufkuov,  ijuoted 
in  Sir  W.  Hamilton's  Lectures,  I.  331. 


472  THE  PHYSICAL   BASIS   OF  MIXD, 

Although  during  sleep  the  nervous  centres  have  l)y 
no  means  their  full  activity,  they  are  always  capable 
of  responding  to  a  stimulus,  and  sensation  will  always  be 
produced.  When  the  servant  taps  at  your  bedroom  door 
in  the  morning,  you  are  said  not  to  hear  the  tap,  if  asleep; 
you  do  not  perceive  it ;  but  the  sound  reaches  and  rouses 
you  nevertheless,  since  when  the  second  tap  comes,  al- 
though no  louder,  you  distinctly  recognize  it.  In  ether- 
ized patients,  sensation  is  constantly  observed  returning 
before  any  consciousness  of  what  is  going  on  returns.  "  I 
was  called,"  says  ]\Ir.  Potter,  "  to  give  chloroform  to  a  lady 
for  the  extraction  of  ten  teeth.  The  first  five  were  ex- 
tracted without  the  slightest  movement,  but  as  the  opera- 
tion proceeded,  sensation  returned,  and  I  was  obliged  to 
use  considerable  force  to  keep  her  in  the  chair  during  the 
extraction  of  the  last  tooth.  She  came  to  herself  very 
shortly  after,  and  was  delighted  to  find  she  had  got  over 
all  her  troubles  without  having  felt  it  the  least  in  the 
world."* 

5.  We  do  not  see  the  stars  at  noonday,  yet  they  shine. 
We  do  not  see  the  sunbeams  playing  among  the  leaves  on 
a  cloudy  day,  yet  it  is  by  these  beams  that  the  leaves  and 
all  otlier  objects  are  visible.  There  is  a  general  illumina- 
tion from  the  sun  and  stars,  but  of  this  we  are  seldom 
aware,  because  our  attention  falls  upon  the  illumined 
objects,  brighter  or  darker  than  this  general  tone.  There 
is  a  sort  of  analogy  to  this  ih  the  general  Consciousness, 
which  is  composed  of  the  sum  of  sensations  excited  by 
the  incessant  simultaneous  action  of  internal  and  external 
stimuli.  This  forms,  as  it  were,  the  daylight  of  our  exist- 
ence. We  do  not  habitually  attend  to  it,  because  attention 
falls  on  those  particular  sensations  of  pleasure  or  of  pain, 
of  greater  or  of  less  intensity,  which  usurp  a  prominence 
among  the  objects  of  the  sensitive  panorama.     But  just 

*  Lancet,  10th  July,  1858. 


THE   REFLEX   THEORY.  473 

as  we  need  the  daylight  to  see  tlie  brilliant  and  the  sombre 
forms  of  things,  we  need  this  living  Consciousness  to  feel 
the  pleasures  and  the  pains  of  life.  It  is  therefore  as 
erroneous  to  imagine  that  we  have  no  other  sensations 
than  those  which  we  distinctly  recognize  —  as  to  imagine 
that  we  see  no  other  light  than  what  is  reflected  from  the 
sliops  and  equipages,  the  colors  and  splendors  which  arrest 
the  eye. 

The  amount  of  light  received  from  the  stars  may  be 
small,  but  it  is  present.  The  greater  glory  of  the  sun- 
liglit  may  render  this  starlight  inappreciable,  but  it  does 
not  render  it  inoperative.  In  like  manner  the  amount  of 
sensation  received  from  some  of  the  centres  may  be  in- 
appreciable in  the  presence  of  more  massive  influences 
IVom  other  centres ;  but  though  inappreciable  it  cannot  be 
inoperative  —  it  must  form  an  integer  in  the  sum. 

6.  The  reader's  daily  experience  will  assure  him  that 
over  and  above  all  the  particular  sensations  capable  of 
being  separately  recognized,  there  is  a  general  stream 
of  Sensation  which  constitutes  his  feeling  of  existence  — 
the  Consciousness  of  himself  as  a  sensitive  being.  The 
ebullient  energy  which  one  day  exalts  life,  and  the  mourn- 
ful depression  which  the  next  day  renders  life  a  burden 
almost  intolerable,  are  feelings  not  referable  to  any  of  the 
particular  sensations,  but  arise  from  the  massive  yet  ob- 
scure sensibilities  of  the  viscera,  wliich  form  so  important 
a  part  of  the  general  stream  of  Sensation.  Some  of  these 
may  emerge  into  distinct  recognition.  We  may  feel  tlie 
lieart  beat,  the  intestines  move,  tlie  glands  secrete ;  any- 
thing unusual  in  their  action  will  force  itself  on  our 
attention. 

"  What  we  have  been  long  used  to,"  says  Whytt,  "  we 
become  scarcely  sensible  of;  while  things  which  are  new, 
though  much  more  trifling,  and  of  weaker  impression, 
affect  us  remarkably.     Thus  he  who  is  wont  to  spend  his 


474  THE  PHYSICAL  BASIS   OF  MIND. 

time  in  the  country  is  surprisingly  affected,  upon  first 
coming-  into  a  populous  city,  with  the  noise  and  bustle 
which  prevail  there :  of  this,  however,  he  becomes  daily 
less  sensible,  till  at  length  he  regards  it  no  more  than  they 
■who  have  been  used  to  it  all  their  lifetime.  The  same 
seems  to  be  the  case  also  with  what  passes  within  our 
bodies.  Few  persons  in  health  feel  the  beating  of  their 
heart,  though  it  strikes  against  their  ribs  with  considerable 
force  every  second ;  whereas  the  motion  of  a  fly  upon  one's 
face  or  hands  occasions  a  very  sensible  and  uneasy  titil- 
lation.  The  pulsation  of  the  great  aorta  itself  is  \vholly 
unobserved  by  us ;  yet  the  unusual  beating  of  a  small 
artery  in  any  of  the  fingers  becomes  very  remarkable." 

7.  A  large  amount  of  sensation  is  derived  from  the 
muscular  sense,  yet  we  are  not  aware  of  the  nice  adjust- 
ments of  the  muscles,  regulated  by  this  sensibility,  wheu 
we  sit  or  walk.  Xo  sooner  are  we  placed  in  an  exceptional 
position,  as  in  walking  on  a  narrow  ledge,  than  we  become 
distinctly  aware  of  the  effort  required  to  preserve  equi- 
librium. It  is  not  the  novelty  of  the  position  which  has 
increased  our  sensibility ;  that  has  only  caused  us  to 
attend  to  our  sensations.  In  like  manner,  the  various 
streams  of  sensation  which  make  up  our  general  sense  of 
existence,  separately  escape  notice  nntil  one  of  them 
becomes  obstructed,  or  increases  in  impetuosity.  When 
we  are  seated  at  a  windov/,  and  look  out  at  the  trees  and 
sky,  we  are  so  occupied  with  the  aspects  and  the  voices 
of  external  Nature,  that  no  attention  whatever  is  given  to 
the  fact  of  our  own  existence ;  yet  all  this  while  there 
has  been  a  massive  and  diffusive  feeling  arising  from  the 
organic  processes ;  and  of  this  we  become  distinctly  aware 
if  we  close  our  eyes,  shut  off  all  sounds,  and  abstract  the 
sensations  of  touch  and  temperature — it  is  then  perceived 
as  a  vast  and  powerful  stream  of  sensation,  belonging  to 
none  of  the  special  Senses,  but  to  the  System  as  a  whole. 


THE  EEFLEX   THEORY.  475 

It  is  on  this  general  stream  that  depend  those  well-known 
but  indescribable  states  named  "  feeling  well "  and  ''  feel- 
ing ill "  —  the  hien  etre  and  malaise  of  every  day.  Of  two 
men  looking  from  the  same  window,  on  the  same  land- 
scape, one  will  be  moved  to  unutterable  sadness,  yearning 
for  the  peace  of  death ;  the  other  will  feel  his  soul  suf- 
fused with  serenity  and  content :  the  one  has  a  gloomy 
background,  into  which  the  sensations  excited  by  the 
landscape  are  merged ;  the  other  has  a  happy  background, 
on  which  the  sensations  j)lay  like  ripples  on  a  sunny  lake. 
The  tone  of  each  man's  feeling  is  determined  by  the  state 
of  his  general  consciousness.  Except  in  matters  of  pure 
demonstration,  we  are  all  determined  towards  certain 
conclusions  as  much  by  this  general  consciou.sness  as  by 
logic.  Our  philosophy,  when  not  borrowed,  is  little  more 
than  the  expression  of  our  personality. 

8.  Having  thus  explained  the  relation  of  particular 
sensations  to  the  general  state  of  Consciousness  consid- 
ered as  the  function  of  the  whole  organism,  we  may 
henceforward  speak  of  particular  sentient  states,  as  we 
speak  of  particular  organs  and  functions,  all  the  while 
presupposing  that  the  organs  and  functions  necessarily 
involve  the  organism,  since  apart  from  the  organism  they 
have  no  such  significance.  The  reaction  of  a  sensory 
organ  is  therefore  always  a  sentient  plienomenon.  Apart 
from  the  living  organism  there  can  be  no  such  vital  re- 
action, but  only  a  physical  reaction.  It  is  commonly 
supposed  that  sensation  is  simply  the  molecular  excitation 
of  the  cerebrum ;  yet  no  one  will  maintain  that  if  the 
cerebrum  of  a  corpse  be  excited,  by  a  galvanic  current 
sent  through  the  optic  nerve,  for  instance,  this  excitation 
will  be  a  sensation.  Whence  we  may  conclude  that  it 
is  not  the  physical  reaction  or  stimulus  which  constitutes 
sensation,  but  the  physiological  reaction  of  the  living 
organism. 


476  THE  PHYSICAL  BASIS  OF   MIND. 

9.  Now  this  is  the  point  which  the  advocates  of  the 
Reflex  Tlieory,  implicitly  or  explicitly,  always  deny.  Let 
us  trace  the  origin  of  the  fallacy,  if  possible.  When  we 
remove  the  eye  from  a  recently  killed  animal,  and  let 
a  beam  of  light  fall  on  it,  the  pupil  contracts.  This  is  a 
purely  mechanical  action ;  no  one  would  suggest  that 
a  sensation  determined  it.  When  we  remove  the  leg,  and 
irritate  its  nerve,  the  leg  is  jerked  out.  This  is  also  a 
I)urely  mechanical  action.  When  we  remove  the  brain 
Irom  an  animal,  and  pinch  its  toes,  the  leg  is  withdrawn 
or  the  pincers  are  pushed  aside.  Is  this  equally  a  purely 
mechanical  action  ?     And  if  not,  why  not  ? 

The  Reflex  Theory  would  have  us  believe  that  all  three 
cases  were  mechanical,  at  least  in  so  far  as  they  were  all 
destitute  of  sentient  co-operation,  the  ground  for  this 
conclusion  being  the  hypothesis  that  the  braiu  is  the  ex- 
clusive seat  of  sensation.  The  Reflex  Theory  further  con- 
cludes that  since  these,  and  analogous  actions,  are  per- 
formed when  the  brain  is  removed,  they,  being  thus 
independent  of  sentience,  may  be  performed  when  the 
brain  is  present  without  any  co-operation  of  sentience. 
The  grounds  for  this  conclusion  being  the  facts  that  in 
the  normal  state  of  the  organism  there  are  many  actions 
of  which  we  are  sometimes  conscious,  and  at  other  times 
unconscious ;  and  some  actions  —  such  as  the  dilatation 
and  contraction  of  the  pupil  —  of  which  we  are  never 
conscious.  This  observation  of  parts  detaclied  from  the 
organism  seems  confirmed  by  observation  of  actions  pass- 
ing in  our  own  organisms,  both  converging  to  the  con- 
clusion that  the  actions  in  question  are  purely  mechanical, 
involving  no  sentience  whatever.  We  are  taught,  there- 
fore, that  there  is  besides  the  sentient  mechanism,  to 
which  all  conscious  actions  are  referred,  a  reflex  mechan- 
ism, to  which  all  unconscious  actions  are  referred.  The 
cerebro-spinal  axis,  acting  as  a  whole,  constitutes  the  first; 


THE   REFLEX   THEORY.  477 

the  spinal  axis,  acting  without  the  co-operation  of  the 
cerebrum,  constitutes  the  second. 

10.  Before  proceeding  with  our  exposition  of  the  theory- 
it  may  be  Avell  to  state  two  considerations  which  must 
be  constantly  in  view.  If  it  should  appear  that  there  is 
any  reasonable  evidence  for  refusing  to  limit  Sensibility 
to  the  cerebrum  —  and  this  evidence  I  shall  adduce  — 
the  Keflex  Tlieory  must  obviously  be  remodelled.  Nor 
is  this  all.  We  might  see  overwhelming  evidence  in 
favor  of  the  hypothesis  that  the  cerebrum  is  the  exclusive 
seat  of  Sensibility,  and  still  reject  as  a  fallacy  the  con- 
clusion that  because  certain  actions  can  be  performed  in 
the  absence  of  the  cerebrum,  therefore  those  actions  in 
the  normal  organism  are  likewise  performed  without  cere- 
bral co-operation.  I  mean  that  it  is  a  fallacy  to  conclude 
from  the  contractions  of  the  pupil,  and  the  jerking  of  the 
leg,  when  eye  and  leg  are  detached  from  the  organism, 
that  therefore  when  eye  and  leg  form  integral  parts  of 
the  organism,  such  contractions  and  jerkings  are  mechani- 
cal reflexes  without  sentient  conditions.  And  the  fallacy 
is  analogous  to  that  which  would  conclude  from  the  ob- 
servations of  a  mechanical  automaton,  that  similar  ap- 
pearances in  a  vital  organism  were  equally  automatic  and 
mechanical.  So  long  as  both  sets  of  phenomena  are 
apprehended  simply  as  they  appear  to  the  senfee  of  sight, 
they  may  be  indistinguishable ;  but  no  sooner  do  we 
appreliend  them  tlirough  other  modes,  and  examine  the 
modes  of  production  of  the  plienomena,  than  we  come 
upon  cardinal  differences.  A  limb  detached  from  the 
organism  is  like  a  plirase  detached  from  a  sentence :  it 
has  lo.st  its  vital  significance,  its  functional  value,  in  los- 
ing its  connection  with  the  other  parts.  The  wliole  sen- 
tence is  necessary  for  the  slightest  meaning  of  its  con- 
stituent words,  and  each  word  is  a  language-clement  only 
when  ideally  or  verbally  connected  with  the  other  words 


478  THE   niYSICAL   BASIS   OF   MIND. 

required  to  form  a  sentence ;  without  subject,  predicate, 
rtud  copula,  no  sentence  can  be  formed.  So  the  organic 
counexus  of  parts  with  a  living  whole  is  necessary  for 
the  simplest  function  of  each  orgaji ;  and  a  limb,  or  any 
other  part,  is  a  physiological  element  only  when  (ideally 
or  really)  an  integral  of  a  vital  whole.  The  organism 
may  be  truncated  by  the  removal  of  certain  parts,  as  the 
sentence  may  be  abbreviated  by  the  removal  of  certain 
phrases;  but  so  long  as  subject,  predicate,  and  copula 
remain,  there  is  a  meaning  in  the  sentence ;  and  so  long 
as  the  organic  connexus  needful  for  vitality  remains^ 
there  will  be  vital  function.  The  eye  detached  from  the 
organism  is  no  longer  a  part  of  the  living  whole,  it  no 
longer  lives,  its  phenomena  cease  to  be  vital,  its  move- 
ments cease  to  have  sentient  conditions.  The  move- 
ments of  the  pupil  may  seem  to  be  the  same  as  those  of 
the  living  eye ;  but  when  we  come  to  examine  their 
modes  of  production,  we  learn  that  they  are  not  the  same. 
The  stimulus  of  light  falling  on  the  eye  in  the  two  cases 
necessarily  has  a  different  effect,  because  the  effect  is  the 
result  of  the  co-operating  causes,  and  the  co-operation  in 
the  one  case  is  that  of  a  lifeless  organ,  in  the  other  that 
of  a  living  organism.  So  long  as  the  eye  forms  an  inte- 
gral part  of  the  organism,  every  stimulus  acting  on  the 
eye  necessarily  acts  on  the  organism,  and  every  reaction 
of  the  organ  is  necessarily  conditioned  by  the  state  of 
the  organism.  Further,  every  stimulation  of  a  sensory 
nerve  necessarily  affects  the  general  sensorium,  since  the 
whole  nervous  system  is  structurally  continuous  and  func- 
tionally co-operant.  (See  Prob.  II.  §  16.)  Therefore,  the 
stimulation  of  the  eye,  although  too  faint  to  be  discrimi- 
nated as  a  conscious  sensation,  must  enter  as  a  sentient 
tremor  into  the  general  stream  of  Sentience ;  and  although 
we  have  no  test  delicate  enough  to  reveal  this  operation, 
we  know  the  obverse,  operation  of  conscious  sensation  on 


THE   KEFLEX   THEORY.  479 

the  movements  of  the  pupil  —  in  surprise,  for  example, 
the  pupil  is  dilated. 

11.  There  are  still  stronger  reasons  for  asserting  that 
the  spinal  reflexes  are  necessarily  conditioned  by  the 
general  state  of  the  sensorium,  so  that  in  the  normal 
organism  we  cannot  legitimately  exclude  them  from  Sen- 
tience ;  and  the  Eeflex  Theory  is  therefore  unphysiologi- 
cal,  even  on  the  hypothesis  that  the  cerebrum  is  the 
exclusive  seat  of  Sensibility.  This  hypothesis,  however, 
seems  to  me  untenable ;  and  all  the  observed  facts  which 
it  is  invented  to  explain  admit  of  a  far  more  consistent 
explanation.  It  is  irrational  to  suppose  that  a  limb,  de- 
tached from  the  body,  felt  the  stimulus  which  caused  its 
muscles  to  contract.  The  limb  is  not  a  living  organism, 
having  a  sentient  mechanism  in  its  nervous  mechanism. 
Not  less  irrational  is  it  to  suppose  that  when  the  limb 
forms  an  integral  part  of  a  living  organism,  with  a  sen- 
tient mechanism  of  nerves  and  nerve-centres,  this  organism 
does  not  react  on  the  stimulus  which  excites  the  muscles 
of  the  limb  to  contract ;  nor,  pursuing  the  same  train  of 
reasoning,  is  it  irrational  to  suppose  that  when  this  liv- 
ing organism  has  been  mutilated,  and  certain  parts  de- 
stroyed, which  do  not  in  tlieir  destruction  prevent  the 
counexus  of  tlie  rest,  but  leave  intact  a  sentient  mechan- 
ism of  nerves  and  nerve-centres,  then  also  this  truncated 
organism  still  reacts  as  a  whole,  still  feels  the  stimulus 
wliich  causes  the  muscles  of  the  limb  to  contract.  Hy- 
pothesis for  hypothesis,  we  may  at  least  say  that  the  one 
is  as  reasonable  as  tlie  other.  And  I  shall  1)(;  disap- 
pointed if,  when  the  reader  has  gone  through  all  the  evi- 
dence hereafter  to  be  adduced,  he  does  not  conclude  that 
the  hypothesis  which  a.ssigns  Sensibility  to  the  nervous 
mechanism  as  a  wliolo  is  not  the  more  acceptable  of  the 
two. 

12.  Let  us  now  pursue  our  exposition  of  the  licflex 


480  THE  niYsiCAL  basis  of  mind. 

Theory.  All  that  ^vc  have  endeavored  to  establish  re- 
specting the  essential  identity  of  tlie  processes  in  conscious 
and  unconscious  states,  and  voluntary  and  involuntary 
actions,  —  an  identity  which  does  not  exclude  differences 
of  degree  corresponding  with  these  different  terms,  —  is 
ignored  or  denied  in  the  Eeflex  Theory.  Whereas  I  sup- 
pose all  processes  to  be  reflex  processes,  some  of  them  hav- 
ing the  voluntary,  others  the  involuntary  character,  phys- 
iologists generally  distinguish  the  involuntary  as  reflex, 
and  invent  for  this  class  a  special  mechanism.  Accord- 
ing to  Marshall  Hall,  who  originated  the  modern  form 
of  this  theory,  actions  are  divisible  into  four  distinct 
classes :  the  voluntary,  dependent  on  the  brain ;  tlie  in- 
voluntary, dependent  on  the  irritability  of  the  muscular 
fibre ;  the  respiratory,  wherein  "  the  motive  influence 
passes  in  a  direct  line  from  one  point  of  the  nervous  sys- 
tem to  certain  muscles " ;  and  the  reflex,  dependent  on 
the  "  true  spinal  system "  of  inciclent-excitor  nerves,  and 
of  reflex-motor  nerves.  These  last-named  actions  are  pro- 
duced when  an  imjjrcssion  on  the  sensitive  surface  is  con- 
veyed, by  an  excitor-nerve,  to  the  spinal  cord,  and  is  there 
reflected  back  on  the  muscles  by  a  corresponding  motor- 
nerve.  In  this  process  no  sensation  whatever  occurs. 
The  action  is  purely  reflex,  purely  excito-motor  —  like  the 
action  of  an  ordinary  mechanism.* 

Miiller,  who  shares  with  Marshall  Hall  the  glory  of 
having  established  this  classification,  thinks  that  although 
the  absence  of  sensation  is  a  characteristic  of  the  reflex 
actions,  these  actions  may  be,  and  are  at  times,  accompa- 
nied by  sensation.  "The  view  I  take  of  the  matter  is  the 
following :  Irritation  of  sensitive  fibres  of  a  spinal  nerve 
excites  primarily  a  centripetal  action  of  the  nervous  prin- 

*  Marshall  Hall  in  Philos.  Trans.,  1833.  Lectures  on  the  Nervous 
System  and  its  Diseases,  1836.  A^ew  Menwir  on  the  Nervous  System, 
1843. 


THE   REFLEX   THEORY.  481 

ciple,  conveying  the  impression  to  the  spinal  cord ;  if  the 
centripetal  action  can  then  be  continued  to  the  scnsorium 
commune,  a  true  sensation  is  the  result;  if,  on  account  of 
division  of  the  cord,  it  cannot  be  communicated  to  the 
sensorium,  it  still  exerts  its  whole  influence  upon  the 
cord ;  in  both  cases  a  reflex  motor  action  may  be  the 
result."  * 

13.  It  is  needless  nowadays  to  point  out  that  tlie  ex- 
istence of  a  distinct  system  of  excito-motor  nerves  belongs 
to  Imaginary  Anatomy ;  but  it  is  not  needless  to  point 
out  that  the  Imaginary  Physiology  founded  on  it  still  sur- 
vives. The  hypothetical  process  seems  to  me  not  less  at 
variance  with  observation  and  induction,  than  the  hypo- 
thetical structure  invented  for  its  basis.  We  have  already 
seen  that  w^hat  Anatomy  positively  teaches  is  totally  un- 
like the  reflex  mechanism  popularly  imagined.  The  sen- 
sory nerve  is  not  seen  to  enter  the  spinal  cord  at  one 
point,  and  pass  over  to  a  corresponding  point  of  exit ;  it 
is  seen  to  enter  the  gray  substance,  which  is  continuous 
throughout  the  spinal  cord ;  it  is  there  lost  to  view,  its 
course  being  untraceable.  Nor  does  the  physiological 
process  present  the  aspect  demanded  by  the  theory :  it  is 
not  that  of  a  direct  and  uniform  reflexion,  such  as  would 
result  from  an  impression  on  one  spot  transmitted  across 
the  spinal  cord  to  a  corresponding  motor-nerve.  The 
impression  is  sometimes  followed  by  one  movement,  some- 
times by  another  very  different  movement,  each  deter- 
mined by  the  state  of  neural  tension  in  the  whole  central 
system. 

p]ven  the  facts  on  which  the  Ileflex  Theory  is  based  are 
differently  interpreted  by  different  physiologists.  Van 
Deen,  for  instance,  considers  tliat  lieflexion  takes  place 
without  Volition,  but  not  without  Sensation ;  and  Budge, 
that  it  takes  place  without  perception  ( Vorstellung).    And 

*  JliJi.LER,  Physiology,  I.  721. 
VOL.  III.  21  E  E 


482  THE  PHYSICAL  basis  of  mind. 

■when  it  is  remembered  that  most  of  the  reflex  actions  will 
be  accompanied  by  distinct  consciousness  whenever  atten- 
tion is  directed  to  them,  or  the  vividness  of  the  stimu- 
lation is  slightly  increased,  it  becomes  evident  that  the 
absence  of  Consciousness  (discrimination)  is  not  the  dif- 
ferentia of  Eeflex  action. 

14.  Nor  can  the  absence  of  spontaneity  be  accepted  as 
a  differentia.  All  actions  are  excited  by  stimulation, 
internal  or  external.  What  are  called  the  spontaneous 
actions  are  simply  those  which  are  prompted  by  internal, 
or  by  not  recognizable  stimuli ;  and  could  we  see  the  pro- 
cess, we  should  see  a  neural  change  initiated  by  some 
stimulation,  whether  the  change  was  conscious  and  vo- 
litional, or  unconscious  and  automatic.  The  dog  rising 
from  sleep  and  restlessly  moving  about,  is  acting  sponta- 
neously, whether  the  stimulation  which  awakens  him  be 
a  sensation  of  hunger,  a  sensation  of  sound,  the  sharp  pain 
of  a  prick,  or  a  dash  of  cold  water.  If  he  wags  his  tail  at 
the  sight  of  his  master,  or  w^ags  it  when  dreaming,  the 
stimulation  is  said  to  be  spontaneous ;  but  if  after  his 
spinal  cord  has  been  divided  the  tail  wags  when  his  abdo- 
men is  tickled,  the  action  is  called  .reflex.  In  all  three 
cases  there  has  been  a  process  of  excitation  and  reflexion. 

15.  The  advocates  of  the  Reflex  Theory  insist  that 
spontaneity  is  always  absent  in  brainless  animals;  whence 
the  conclusion  that  the  brain  is  the  exclusive  organ  of 
sensation.  But  the  fact  asserted  is  contradicted  by  the 
evidence.  No  experimenter  can  have  failed  to  observe 
numberless  examples  of  spontaneity  in  brainless  animals. 
Many  examples  have  already  been  incidentally  noticed  in 
previous  pages.  Let  me  add  one  more  from  my  notes : 
I  decapitated  a  toad  and  a  triton,  and  divided  the  spinal 
cord  of  another  triton  and  a  frog.  At  first  the  movements 
of  the  decapitated  animals  were  insignificant ;  but  on  the 
second  day  the  headless  toad  was  quite  as  lively  as  the 


THE   EEFLEX   THEORY.  483 

froo-  •  and  the  headless  triton  little  less  so  than  his  com- 
panion  with  cord  divided  hut  hrain  intact.  I  have,  at  the 
time  of  writing  this,  a  frog  whose  cord  was  divided  some 
weeks  ago.  He  remains  almost  motionless  unless  when 
touched ;  he  is  generally  found  in  the  same  spot,  and  in 
the  same  attitude  to-day  as  yesterday,  unless  touched,  or 
unless  the  table  be  shaken.  He  occasionally  moves  one 
of  the  forelegs ;  occasionally  one  of  the  hind-legs ;  but 
without  changing  his  position.  If  he  M^ere  brainless,  this 
quiescence  would  be  cited  in  proof  of  the  absence  of  spon- 
taneity in  the  absence  of  the  brain  ;  but  this  conclusion 
would  be  fallacious,  and  is  seen  to  be  so  in  the  sponta- 
neous movements  of  his  companion  who  has  no  brain. 

16.  With  spontaneity  is  associated  the  idea  of  volition, 
and  with  volition  choice.  Now  I  admit  that  it  is  com- 
plicating the  question  to  ask  any  one  to  conceive  a  head- 
less animal  choosing  one  action  rather  than  another ;  but 
it  is  equally  difficult  to  reconcile  ourselves  to  the  idea  of 
"  choice  "  in  contemplating  tlie  actions  of  a  mollusc.  In 
what  sense  we  can  speak  of  the  volition  of  a  mollusc  or  an 
insect  has  already  been  considered  (p.  408).  When  a  man 
in  a  fit  of  coughing  seizes  a  glass  of  water  to  allay  the 
tickling  in  his  throat,  we  have  no  hesitation  in  declaring 
this  to  be  volitional  —  and  the  remedy  to  be  chosen.  But 
when  a  brainless  animal  adopts  some  unusual  means,  after 
the  failure  of  the  usual  means,  to  allay  an  irritation,  we 
still  hesitate  to  call  the  action  volitional.  I  see,  however, 
no  objection  to  calling  it  the  adaptation  of  a  sensitive 
mechanism  which  is  markedly  unlike  any  inorganic  mech- 
anism. 

Place  a  child  of  two  or  tlu'ce  years  old  ujjou  his  back, 
and  tickle  his  right  cheek  witli  a  feather.  lie  will  prob- 
ably move  his  head  away.  Continue  tickling,  and  he  will 
rub  the  spot  with  his  riglit  \\^m\,  never  iising  the  left  hand 
for  the  riglit  clieek,  so  long  as  the  right  hand  is  free  ;  but 


484  THE   PHYSICAL   BASIS   OF   MIND. 

if  you  hold  his  right  hand,  he  will  use  the  left.  Does  any- 
one dispute  the  voluntary  character  of  these  actions  ? 

Now  compare  the  actions  of  the  sleeping  child  under 
similar  circumstances,  and  their  sequence  will  be  pre- 
cisely similar.  This  contrast  is  the  more  illustrative, 
because  physiologists  generally  assume  that  in  sleep  con- 
sciousness and  volition  are  suspended.  They  say :  "  The 
brain  sleeps,  the  spinal  cord  never ;  volition  and  sensation 
may  be  suspended,  but  not  reflex  action."  This  proposi- 
tion is  extremely  questionable  ;  yet  it  is  indispensable  to 
the  reflex  theory ;  because  unless  sensation  and  volition 
are  suspended  during  sleep,  we  must  admit  that  they  can 
act,  without  at  the  same  time  calling  into  activity  that 
degree  of  sensibility  which  is  supposed  to  constitute  con- 
sciousness. The  child  moves  in  his  sleep,  defends  him- 
self in  his  sleep  ;  but  he  is  not  "  aware  "  of  it. 

"  Children,"  says  Pflliger,  "  sleep  more  soundly  than 
adults,  and  seem  to  be  more  sensitive  in  sleep.  I  tickled 
the  right  nostril  of  a  three-year-old  boy.  He  at  once 
raised  his  right  hand  to  push  me  away,  and  then  rubbed 
the  place.  When  I  tickled  the  left  nostril  he  raised  the 
left  hand.  I  then  softly  drew  both  arms  down,  and  laid 
them  close  to  the  body,  embedding  the  left  arm  in  the 
clothes,  and  placing  on  it  a  pillow,  by  gentle  pressure  on 
which  I  could  keep  the  arm  down  without  awakening 
him.  Having  done  this  I  tickled  his  left  nostril.  He  at 
once  began  to  move  the  imprisoned  arm,  but  could  not 
reach  his  face  with  it,  because  I  held  it  firmly  though 
gently  down.  He  now  drew  his  head  aside,  and  I  con- 
tinued tickling,  whereupon  he  raised  the  riffht  hand,  and 
with  it  rubbed  the  left  nostril  —  an  action  he  never  per- 
formed when  the  left  hand  was  free." 

17.  This  simple  but  ingenious  experiment  establishes 
one  important  point,  namely,  that  the  so-called  reflex 
actions  observed  in  sleep  are  determined  by  sensation  and 


THE   EEFLEX   THEORY.  485 

volition.  The  sleeping  child  behaves  exactly  as  the 
waking  child  behaved ;  the  only  difference  being  in  the 
energy  and  rapidity  of  the  actions.  If  the  waking  child 
felt  and  willed,  surely  the  sleeping  child,  wlien  it  per- 
formed precisely  similar  actions,  cannot  be  said  to  have 
felt  nothing,  willed  nothing  ?  It  is  not  at  one  moment  a 
sentient  organism,  and  at  the  next  an  insentient  mech- 
anism. 

It  is  possible  to  meet  this  case  by  assuming  that  the 
child  was  nearly  awake,  and  that  a  dim  consciousness  was 
aroused  by  the  tickling,  so  that  the  cerebral  activity 
was  in  fact  awakened.  But,  plausible  as  this  explanation 
may  be  (and  I  am  the  more  ready  to  admit  it  because  I 
l)elieve  the  brain  always  co-operates  when  it  is  present), 
it  altogether  fails  when  we  come  to  experiments  on  de- 
capitated animals.  If  any  one  will  institute  a  series  of 
such  experiments,  taking  care  to  compare  the  actions 
of  the  animal  before  and  after  decapitation,  he  will  per- 
ceive that  there  is  no  more  difference  between  them  than 
between  those  of  the  sleeping  and  the  waking  child. 

18.  Even  more  striking  is  the  following  experiment, 
devised  by  Pflliger,  which  I  have  verified,  and  varied, 
many  times :  A  frog  is  decapitated,  or  its  brain  is  re- 
moved.* When  it  has  recovered  from  the  effect  of  the 
ether,  and  manifests  lively  sensiljility,  we  place  it  on  its 
back,  and  touch,  with  acetic  acid,  the  skin  of  its  thigh 
just  above  the  condt/las  intcrnus  fcmoris.  (Let  the  reader 
imagine  his  own  shoulder  burnt  at  the  point  wliere  it  can 
be  reached  with  the  thumb  of  the  same  arm,  and  lie  will 

*  It  is  better  simply  to  remove  the  brain,  than  to  remove  the  whole 
head,  whieh  causes  a  serious  loss  of  blood.  An  etherized  animal  may  be 
()l)erated  on  with  case  and  accuracy.  For  many  experiments,  mere  divis- 
ion of  the  spinal  cord  is  better  than  decapitation.  Great  variations  in 
the  results  must  be  expected,  because  the  condition  of  the  animal,  its 
age  and  sex  —  whether  fasting  or  digesting  —  whether  the  season  lie 
spring  or  summer  —  and  a  hundred  other  causes,  complicate  the  ex- 
pi'iimont. 


486  THE   PITYSICAL  BASIS   OF  MIXD. 

realize  the  operation.)  No  sooner  does  the  acid  begin  to 
burn  than  the  frog  stretches  out  tlie  other  leg,  so  that  its 
body  is  somewluit  drawn  towards  it.  The  leg  that  has 
been  burnt  is  now  bent,  and  the  back  of  the  foot  is  ap- 
plied to  the  spot,  rubbing  the  acid  away — just  as  your 
thumb  might  rub  your  shoulder.  This  is  very  like  the 
action  of  tlie  tickled  child,  who  always  uses  the  right 
hand  to  rub  the  right  cheek,  unless  it  be  held ;  but  when 
the  child's  right  hand  is  prevented  from  rubbing,  the  left 
will  be  employed ;  and  precisely  this  do  we  observe  with 
the  brainless  frog :  prevent  it  from  using  its  right  leg,  and 
it  will  use  its  left ! 

This  has  been  proved  by  decapitating  another  frog,  and 
cutting  off  the  foot  of  the  leg  which  is  to  be  irritated. 
No  soouer  is  the  acid  applied,  than  the  leg  is  bent  as  be- 
fore, and  the  stump  is  moved  to  and  fro,  as  if  to  rub  away 
the  acid.  But  the  acid  is  not  rubbed  away,  and  the  ani- 
mal becomes  restless,  as  if  trying  to  hit  upon  some  other 
plan  for  freeing  himself  of  the  irritation.  And  it  is 
worthy  of  remark  that  he  often  hits  upon  plans  very 
similar  to  those  which  an  intelligent  human  being  adopts 
under  similar  circumstances.  Thus,  the  irritation  con- 
tinuing, he  will  sometimes  cease  the  vain  efforts  with 
his  stump,  and  stretching  that  leg  straight  out,  bends  tlie 
other  leg  over  towards  the  irritated  spot,  and  rubs  the 
acid  away.  But,  to  show  how  far  this  action  is  from  one 
of  "  mere  mechanism,"  how  far  it  is  from  being  a  direct 
reflex  of  an  impression  on  a  group  of  muscles,  the  frog 
does  not  always  hit  even  on  this  plan.  Sometimes  it 
bends  its  irritated  leg  more  energetically,  and  likewise 
bends  the  body  towards  it,  so  as  to  permit  the  spot  to  be 
rubbed  against  the  flank — just  as  the  child,  when  both 
his  hands  are  held,  will  bend  his  cheek  towards  his 
shoulder  and  rub  it  there. 

19.    It  is  difficult  to  resist  such  evidence  as  is  here 


THE   KEFLEX   THEORY.  487 

manifested.  The  brainless  frog  "chooses"  a  new  plan 
when  the  old  one  fails,  just  as  the  waking  child  chooses. 
And  an  illustration  of  how  sensations  guide  and  deter- 
mine movements,  may  be  seen  in  another  observation  of 
the  brainless  frog,  when,  as  often  happens,  it  does  not  hit 
upon  either  of  the  plans  just  mentioned,  but  remains 
apparently  restless  and  helpless  ;  if  under  these  circum- 
stances we  perform  a  part  of  the  action  for  it,  it  will  com- 
plete what  we  have  hegun :  if  we  rub  the  irritated  leg,  at 
some  distance  from  the  spot  where  the  acid  is,  with  the 
foot  of  the  other,  the  frog  suddenly  avails  itself  of  this 
(juiding  sensation,  and  at  once  directs  its  foot  to  the  irri- 
tated spot. 

In  these  experiments  on  the  triton  and  the  frog,  the 
evidence  of  sensation  and  volition  is  all  the  stronger,  be- 
cause the  reactions  produced  by  irritations  are  not  uni- 
form. If  when  a  decapitated  animal  were  stimulated  it 
always  reacted  in  precisely  the  same  way,  and  never  chose 
new  means  on  the  failure  of  the  old,  it  would  be  conceiv- 
able to  attribute  the  results  to  simple  reflex  action  —  i.  e. 
tlie  mechanical  transference  of  an  impulse  along  a  pre- 
scribed path.  It  is  possible  so  to  conceive  the  breathing, 
or  the  swallowing  mechanism :  the  impression  may  be 
directly  reflected  on  certain  groups  of  muscles.  But  I 
cannot  conceive  a  machine  suddenly  striking  out  new 
methods,  when  the  old  methods  fail.  I  cannot  conceive 
a  machine  thrown  into  disorder  when  its  accustomed 
actions  fail,  and  in  this  disorder  suddenly  lighting  upon 
an  action  likely  to  succeed,  and  continuing  that ;  but  I 
can  conceive  this  to  be  done  by  an  organism,  for  my  own 
experience  and  observation  of  animals  assures  me  that 
this  is  always  the  way  new  lines  of  action  are  adopted. 
And  this  which  is  observed  of  the  unmutilated  animal,  I 
have  just  shown  to  be  observed  of  the  brainless  animal ; 
wherefore  the  conclusion  is,  that  if  ever  tlie  frog  is  sen- 


4S8  THE  riivsiCAL  basis  of  mixd. 

tient,  if  ever  its  actions  are  guided  by  sensation,  they  are 
so  when  its  braiu  is  removed. 

20.  Schroder  van  der  Kolk  thinks  that  rfliiger  was 
deceived  in  attributing  sensation  and  volition  to  the  frog, 
because  the  reflex  actions  are,  he  says,  so  nicely  adapted 
to  their  ends,  that  they  are  undistinguishable  from  volun- 
tary actions.  The  mechanism  is  such  that,  by  means  of 
the  communications  established  between  various  groups 
of  cells,  all  these  actions  adapted  to  an  end  may  be  ex- 
cited by  every  stimulus.  But  I  deny  the  fact.  I  deny 
that  all  the  actions  are  awakened  by  every  stimulus. 
Only  some  few  are  awakened,  and  those  are  not  always 
the  same,  nor  do  they  follow  the  same  order  of  succession. 
One  decapitated  frog  does  not  behave  exactly  like  another 
under  similar  circumstances  ;  does  not  behave  exactly 
like  himself  at  different  seasons ;  unlike  a  machine,  he 
manifests  spontaneity  in  his  actions,  and  volition  in  the 
direction  of  his  actions. 

21.  The  reader  will  notice  that  my  illustrations  show 
these  actions  of  the  brainless  animal  to  have  the  same 
external  characters  as  those  of  the  unmutilated  animals. 
I  am  therefore  not  here  concerned  to  prove  the  psychical 
nature  of  these  actions,  unless  it  be  granted  that  the  un- 
mutilated animal  has  sensation  and  volition.  This  of 
coiirse  can  only  be  inferred,  not  proved.  But  the  infer- 
ence must  not  be  allowed  in  the  one  case  and  refused  in 
the  other.  Young  rabbits  and  puppies  when  taken  from 
their  mothers  manifest  discomfort  by  restless  movement 
and  whining.  Do  they  feel  the  discomfort  they  thus  ex- 
press ?  If  ever  rabbits  and  jDuppies  may  be  said  to  feel, 
we  must  answer.  Yes.  Well,  if  the  brain  be  removed 
from  rabbits  and  puppies,  precisely  similar  phenomena 
are  observed  when  these  young  animals  are  taken  from 
their  mothers.  "  I  observed  the  motions,  which  seemed 
the  result  of  discomfort,  quickly  cease  w^hen  I  warmed 
the  young  rabbit  by  breathing  on  it.     After  a  while  it 


THE   EEFLEX   THEOKY.  489 

was  completely  at  rest,  and  seemed  sunk  in  deep  sleep  ; 
occasionally,  however,  it  moved  one  of  its  legs  without 
any  external  stimulus  having  been  applied,  and  this  not 
spasmodically,  but  in  the  manner  of  a  sleeping  animal."* 
Is  this  cessation  of  the  restlessness,  when  warmth  is  re- 
stored, not  evidence  of  sensation  ?  We  see  an  infant  rest- 
less, struggling,  and  squalling ;  and  we  believe  that  it  is 
hungry,  or  that  some  other  sensations  agitate  it ;  it  is  put 
to  the  breast,  and  its  squalls  subside ;  or  a  finger  is  placed 
in  its  mouth,  and  it  sucks  that,  in  a  peaceful  lull,  for  a 
few  moments,  to  recommence  squalling  when  the  finger 
yields  no  satisfaction.  If  we  accept  these  as  signs  of  sen- 
sation, I  do  not  see  how  we  can  deny  such  sensation  to 
the  brainless  animal  which  will  also  cease  to  cry,  and  will 
suck  the  delusive  finger. 

22.  One  of  the  earliest  advocates  of  tlie  Eefiex  Theory 
sums  up  his  observations  in  these  words :  "  It  is  clear 
that  brainless  animals,  although  without  sensation,  be- 
cause not  endowed  with  mind,  nevertheless,  by  means  of 
external  impressions  which  operate  incessantly  on  them, 
perform  all  the  acts  and  manifest  all  the  activity  of  the 
sentient  animal ;  everything  that  is  effected  sensationally 
and  volitionally,  they  effect  by  means  of  the  organic 
forces  of  the  impressions."  f  Call  Sensibility  one  of  the 
organic  forces,  if  you  please,  but  so  long  as  the  acts  per- 
formed are  not  only  the  same  as  those  of  a  sentient  ani- 
mal, but  are  performed  by  the  same  mechanism,  they 
have  every  claim  to  the  character  of  sensational  acts 
wliich  can  be  urged  in  the  case  of  these  animals  wlien 
the  brain  is  present.  And  the  only  reason  on  which  this 
claim  is  disputed  is  the  assumed  loss  of  aU  sensation  with 
tlie  loss  of  tlie  brain.  Here,  therefore,  lies  the  central 
point  to  be  determined. 

*  VoLKMA.NX,  quoted  by  PflUger. 

t  UxzER,  y/w  Principles  of  Physiology  (translated  for  tlie  Sydenham 
Society),  p.  235. 

21* 


490  THE   PHYSICAL   BASIS   OF  MIND. 


CHAPTER    II. 

DEDUCTIONS  FROM  GENERAL  LAWS. 

23.  The  evidence  is  of  two  kinds :  deductions  from  the 
general  laws  of  nervous  action,  and  inductions  from  par- 
ticular manifestations.  The  former  furnish  a  presump- 
tion, the  latter  a  proof. 

The  central  process  which  initiates  a  reflex  action  may 
be  excited  by  the  external  stimulation  of  a  peripheral 
nerve,  by  the  internal  stimulation  of  a  peripheral  nerve, 
or  by  the  irradiation  from  some  other  part  of  the  central 
tissue.  The  last-named  stimulations  are  the  least  intel- 
ligible, because  they  are  so  varied  and  complex,  and  so 
remote  from  observation  ;  among  them  may  be  placed,  1°, 
the  organized  impulses  of  Instinct  and  Habit,  with  their 
fixed  modes  of  manifestation  ;  2°,  the  organized  impulses 
of  Emotion,  which  are  more  variable  in  their  manifesta- 
tions, because  more  fluctuating  in  their  conditions;  3°,  the 
organized  impulses  of  Intellect,  the  most  variable  of  all. 
Whether  we  shrink  on  the  contact  of  a  cold  substance  or 
on  hearincf  a  sudden  sound,  —  at  the  sif^ht  of  a  terrible 
object,  —  at  the  imaginary  vision  of  the  object,  —  or  be- 
cause we  feign  the  terror  wliich  is  thus  expressed,  —  the 
reflex  mechanism  of  shrinking  is  in  each  case  the  same, 
and  the  neural  process  discharged  on  the  muscles  is  the 
same ;  but  the  state  of  Feeling  which  originated  the 
change  —  or,  in  strictly  physiological  terms,  the  inciting 
neural  process  which  preceded  this  reflex  neural  process  — 
was  in  each  case  somewhat  different,  yet  in  each  case  was 
a  mode  of  Sensibility. 


THE   REFLEX   THEOKY.  491 

24.  The  property  of  Sensibility  belongs  to  the  whole 
central  tissue ;  and  we  have  every  reason  to  believe  that 
unless  it  is  excited  no  reflex  takes  place,  wliereas  when  it 
is  exaggerated  —  as  in  epilepsy,  or  under  strychnine  — 
the  reflex  discharges  are  convulsive.  When  anaesthetics 
are  given,  consciousness  first  disappears,  and  then  re- 
llexion.  When  the  sensorium  is  powerfully  excited  by 
other  stimuli,  the  normal  stimulus  fails  to  excite  either 
consciousness  or  reflexion.  Hence  our  conclusion  is  that 
for  consciousness,  on  the  one  hand,  and  normal  reflexion, 
on  the  other,  the  proximate  condition  is  a  change  in  the 
sensorium;  or  —  to  phrase  it  more  familiarly  —  Feeling 
is  necessary  for  reflex  action. 

The  difficulty  in  apprehending  this  lies  in  the  am- 
biguity of  the  term  Feeling.  Many  readers  who  would 
find  no  difficulty  in  admitting  Sensibility  as  a  necessary 
element  in  reflex  action,  will  resist  the  idea  of  identifying 
Sensibility  with  Feeling.  But  this  repugnance  must  be 
overcome  if  we  are  to  understand  the  various  modes  of 
Sensibility  whicli  represent  Feeling  in  animals,  and  its 
varieties  in  ourselves.  We  understand  how  the  general 
Sensibility  manifests  itself  in  markedly  different  sensa- 
tions —  how  that  of  the  optic  centre  differs  from  that  of 
the  auditory  centre,  and  both  from  a  spinal  centre.  The 
tones  of  a  violin  are  not  the  same  as  the  tones  of  a  vio- 
loncello, botli  differ  from  the  tones  of  a  key-bugle :  yet 
they  all  come  under  the  same  general  laws  of  tonality. 
So,  as  I  often  insist,  the  tissues  in  brain  and  cord  being 
the  same,  their  properties  must  be  the  same,  their  laws 
of  excitation,  irradiation,  and  combination  the  same, 
through  all  the  varieties  in  their  manifestations  due  to 
varieties  of  innervation.  Hence  it  is  that  there  are  reflex 
cerebral  processes  no  less  than  reflex  spinal  processes : 
the  motor  impulse  from  the  hemispheres  on  tlie  corpora 
fitriatu,  or  from  posterior  gray  substance  on  anterior  gray 


492  THE   PHYSICAL   BASIS   OF  MIND. 

substance,  is  similar  to  that  from  the  anterior  gray  sub- 
stance on  the  motor  nerves.  The  difference  in  reflexes 
arises  from  the  terminal  organs ;  as  the  difference  in  sen- 
sations arises  from  the  surfaces  stimulated.  But  not  only 
are  there  reflex  processes  in  the  brain,  of  the  same  order 
as  those  in  the  cord,  there  are  volitional  processes  in  the 
cord  of  the  same  order  as  those  in  the  brain.  And  in 
both  the  processes  are  sometimes  conscious,  sometimes 
unconscious.  No  evidence  suggests  that  in  the  conscious 
action  there  is  a  sensorial  process,  and  a  purely  physical 
process  in  the  unconscious  action  —  only  a  different  rela- 
tion of  one  sensorial  process  to  others. 

25.  Let  us  contrast  a  cerebral  and  a  spinal  process,  in 
respect  to  the  three  stages  of  stimulation,  irradiation,  and 
discharge.  A  luminous  impression  stimulates  my  retina, 
this  excites  my  sensorium,  in  which  second  stage  I  am 
conscious  of  the  luminous  sensation ;  the  final  discharge 
is  a  perception,  or  a  mental  articulation  of  the  name  of 
the  luminous  object.  But  the  irradiation  may  perhaps 
not  have  been  such  as  to  cause  a  conscious  sensation,  be- 
cause the  requisite  neural  elements  were  already  grouped 
in  some  other  way ;  in  this  case  there  is  an  unconscious 
discharge  on  some  motor  group,  and  instead  of  perceiving 
and  naming  the  luminous  object,  I  move  my  head,  or  my 
hand,  or  my  whole  body,  avoiding  the  object,  or  grasping 
at  it.  A  third  issue  is  possible :  the  irradiation,  instead 
of  exciting  a  definite  perception,  or  a  definite  movement, 
may  be  merged  in  the  stream  of  simultaneous  excitations, 
and  thus  form  the  component  of  a  group,  and  the  dis- 
charge of  this  group  will  be  a  perception  or  a  movement. 

It  is  the  same  with  a  spinal  process.  An  impression 
on  the  skin  is  irradiated  in  the  cord,  and  the  response  is 
a  movement,  of  which  we  are  conscious,  or  unconscious. 
Here  also  a  third  issue  is  possible :  the  irradiation  may 
be  merged  in  a  stream  of  simultaneous  excitations,  modi- 


THE   REFLEX   THEORY.  493 

fying  them  and  modified  by  them,  thus  forming  a  com- 
ponent in  some  ulterior  discharge. 

26.  The  obstacle  in  the  way  of  recognizing  that  cere- 
bral processes  and  spinal  processes  are  of  the  same  order 
of  sensorial  phenomena,  and  have  the  same  physiological 
significance  when  considered  irrespective  of  the  group  of 
organs  they  call  into  activity,  is  similar  to  the  obstacle 
which  has  prevented  psychologists  from  recognizing  the 
identity  of  the  logical  process  in  the  combinations  of 
Feeling  and  the  combinations  of  Thought,  i.  e.  the  Logic 
of  Feeling  and  the  Logic  of  Signs.  This  obstacle  is  the 
fixing  attention  on  the  diversity  of  the  effects  when  the 
same  process  operates  with  different  elements.  Because 
the  spinal  cord  manifests  the  phenomena  of  sensation  and 
volition,  we  are  not  to  conclude  that  it  also  manifests 
ideation  and  imagination ;  any  more  than  we  are  to  con- 
clude that  a  mollusc  is  capable  of  musical  feelings  be- 
cause it  is  affected  by  sounds. 

27.  The  careless  confusion  of  general  properties  with 
special  applications  of  those  properties,  and  of  functions 
with  properties,  has  been  a  serious  hindrance  to  the  right 
understanding  of  Sensibility  and  its  operations.  Instead 
of  recognizing  that  the  nervous  system  has  one  general 
mode  of  reaction,  which  remains  the  same  under  every 
variety  of  combination  with  other  systems,  physiologists 
commonly  lose  sight  of  this  general  property,  and  fix  on 
one  mode  of  its  manifestation  as  the  sole  characteristic  of 
Sensibility.  Sometimes  the  mode  fixed  on  is  Pain,  at 
other  times  Attention.  Thus,  when  an  animal  manifests 
no  evidence  of  pain  under  stimulations  which  ordinarily 
excite  severe  pain,  this  is  often  interpreted  as  a  proof  that 
all  sensation  is  absent ;  and  if  with  this  absence  of  pain 
there  is  —  as  there  often  is  —  clear  evidence  of  the  pres- 
ence of  some  other  mode  of  sensil)ility,  the  contradiction 
is  evaded  by  the  assumption  that  what  here  looks  like  evi- 


494  THE  PHYSICAL  BASIS   OF  MIND. 

dence  of  sensation  is  merely  meclianical  reflexion.  One 
would  think  that  Physiology  and  Pathology  had  been 
silent  on  the  facts  of  analgesia  witliout  anaesthesia,  and 
of  so  much  conscious  sensation  which  is  unaccompanied 
by  pain.*  Who  does  not  know  that  a  patient  will  lose 
one  kind  of  sensibility  while  retaining  others  —  cease  to 
feel  pain,  yet  feel  temperature,  or  be  insensible  to  touch, 
yet  exquisitely  alive  to  pain  ?  f  Inasmuch  as  Sensibility 
depends  on  the  condition  of  the  centres,  an  abnormal 
condition  will  obviously  transform  the  reaction  of  the 
centres  into  one  very  unlike  the  normal  reaction.  For 
example,  Antoine  Cros  had  a  patient  who  was  quite  una- 
ble to  feel  the  sensation  of  cold  on  her  left  side  —  every 
cold  object  touching  her  skin  on  that  side  was  felt  as  a 
very  hot  one  ;  whereas  a  hot  object  produced  "  the  sort  of 
sensation  which  followed  the  application  of  an  intermit- 
tent voltaic  current."!  Thus  also  the  experiments  of 
Piose  §  and  others  have  exhibited  the  effects  of  a  dose  of 
Santoniue  in  causing  all  objects  to  be  seen  as  yellow  in 
one  stage,  and  violet  in  another. 

*  Even  so  eminent  an  investigator  as  Goltz  has  fallen  into  tins  confu- 
sion. He  introduces  an  experiment  to  prove  that  the  brainless  frog  is 
insensible  to  pain  by  the  words  "when  an  animal,  placed  under  circum- 
stances which  would  be  very  painful,  makes  no  movement,  although  quite 
capable  of  moving,  the  least  we  can  say  is  that  it  is  improbable  that  the 
animal  has  sensation  "  {Nervenccntrcn  cles  Frosches,  p.  127).  I  need  not 
iliscuss  the  proof  itself,  having  already  done  so  in  Nature,  Vol.  IX.  p. 
84.  The  point  to  which  I  wish  to  call  attention  is  the  confusion  of  insen- 
sibility in  general  with  insensibility  to  pain. 

t  See  DucHENXE,  De  J^lcctrisation  localisee,  p.  398.  Griesinger 
cites  various  examples  of  insane  patients  who  have  burned  the  flesh  off" 
their  bones  while  manifesting  a  total  indifference  to  these  injuries.  3Ia- 
ladies  Mentales,  yj.  94.  Fai.ret  says,  "Nous  avons  vu  plusieurs  fois  des 
alienes  s'inciser,  s'amputer  eux-memes  diverses  parties  du  corps  sans  pa- 
raitre  ressentir  aucune  soufi'ranee."  Ler^ons  cliniques  de  Midicinc  Mcntale, 
1854,  I.  189.  Patients  incapable  of  feeling  the  contact  of  a  hot  iron 
with  their  skin  have  felt  subjective  burnings  in  the  .skin  thus  objectively 
insensible. 

X  Chos,  Les  Fonct ions  super ieiircs  du  Syst.  'lurveux,  1875,  p.  27. 

§   Virchows  Archiv,  Bd.  XXVIII.  p.  30. 


THE   KEFLEX   THEOEY.  495 

28,  If,  then,  certain  alterations  in  the  organic  condi- 
tions are  accompanied  by  a  suppression  or  perversion  of 
some  modes  of  Sensibility,  without  suppressing  the  rest, 
it  is  but  rational  to  suppose  that  profound  disturbances 
of  the  organic  mechanism,  such  as  must  result  from  the 
removal  of  the  l^rain,  will  also  suppress  or  pervert  several 
modes  of  Sensibility,  and  yet  leave  intact  those  modes 
which  belong  to  the  intact  parts  of  the  mechanism.  As- 
suming that  the  spinal  centres  with  the  organs  they 
innervate  are  capable  of  reacting  under  certain  modes 
of  sensation,  these  will  not  necessarily  be  suppressed  by 
removal  of  the  brain  —  all  that  will  thereby  be  sup- 
pressed is  their  co-oj)eration  with  the  brain.  I  know  it 
will  be  said  that  precisely  this  co-operation  is  necessary 
for  sensation ;  and  that  the  spinal  reactions  are  simple 
reflexions  in  which  sensation  has  no  part.  This,  however, 
is  the  position  I  hope  to  turn.  Meanwhile  my  assump- 
tion is  that  sensation  necessarily  plays  a  part  in  the  reflex 
actions  of  the  organism,  and  when  that  organism  is  trun- 
cated, its  actions  are  proportionately  limited,  its  sensations 
less  complex.  The  spinal  cord,  separated  from  encephalic 
connections,  cannot  react  in  the  special  forms  of  Sensation 
known  as  colrtr,  scent,  taste,  sound,  etc.,  because  it  does 
not  innervate  the  organs  of  these  special  senses,  nor  co- 
operate with  their  centres.  But  it  can,  and  does,  react  in 
other  modes :  it  innervates  skin  and  muscles ;  and  the 
sensibilities,  thus  excited,  it  can  also  covihine  and  co-ordi- 
nate. It  has  its  Memory,  and  its  Logic,  just  as  the  brain 
has :  both  no  longer  than  they  are  integral  parts  of  an 
active  living  organism :  neither  wlien  the  organism  is 
inactive  or  dead.  We  do  not  expect  the  retina  to  respond 
in  sounds,  nor  the  ear  to  respond  in  colors :  we  expect 
each  organ  to  have  its  special  mode  of  reaction.  What  is 
common  to  both  is  Sensibility.  What  is  common  to  brain 
and  cord  is  Sensibility  —  and  the  laws  of  Grouping.     In- 


496  THE  PHYSICAL  BASIS   OF  MIND. 

stead  of  marvelling  at  the  disappearance  of  so  many 
modes  of  Sensibility  when  the  brain  is  removed,  our  sur- 
prise should  be  to  find  so  many  evidences  of  Sensibility 
remaining  after  so  profound  a  mutilation  of  the  mech- 
anism. 

29  The  current  hypothesis,  which  assumes  that  the 
brain  is  the  sole  organ  of  the  mind,  the  sole  seat  of  sensa- 
tion, is  a  remnant  of  the  ancient  hypothesis  respecting 
tlie  Soul  and  its  seat ;  and  on  the  whole  I  think  the  an- 
cient hypothesis  is  the  more  rational  of  the  two.  If  the 
Soul  inhabits  the  organism,  using  it  as  an  instrument, 
playing  on  its  organs  as  a  musician  plays  on  his  instru- 
ment, we  are  not  called  upon  to  explain  the  mode  of  oper- 
ation of  this  mysterious  agent ;  but  if  the  Soul  be  the 
subjective  side  of  the  Life,  the  spiritual  aspect  of  the  ma- 
terial organism,  then  since  it  is  a  synthesis  of  all  the 
organic  forces,  the  consensus  of  all  the  sentient  phenom- 
ena, no  one  part  can  usurp  the  prerogatives  of  all,  but  all 
are  requisite  for  each.  And  this  indeed  is  what  few 
physiologists  would  nowadays  dispute.  In  spite  of  their 
localizing  sensation  in  the  cerebral  cells,  they  would  not 
maintain  that  the  cerebral  cells,  nor  even  the  whole  brain, 
could  produce  sensation  —  if  detached  from  the  organism  ; 
the  cheek  of  the  guillotined  victim  may  have  blushed 
when  struck,  but  who  believes  that  the  brain  felt  the  in- 
sult, or  the  blow  ?  Obviously,  therefore,  ^^•hen  we  read 
"that  thought  is  "a  property  of  the  gray  substance  of  the 
brain,  as  gravitation  is  of  matter,"  or  that  the  brain  is  the 
exclusive  organ  of  Sensation,  the  writers  cannot  consist- 
ently carry  out  their  hypothesis  unless  tliey  silently  rein- 
troduce other  organs  as  co-operating  agents ;  for  a  neural 
process  in  the  cerebrum  is  in  itself  no  more  a  sensation 
than  it  is  a  muscular  contraction,  or  a  glandular  secretion : 
the  muscles  must  co-operate  for  the  contraction,  the  gland 
for  the  secretion,  the  neural  process  being  simply  the  ex- 


THE   KEFLEX  THEORY.  497 

citing  cause.  In  like  manner  the  Sensorium  is  necessary 
for  the  sensation,  the  neural  process  —  in  cerebrum,  or 
elsewhere  —  being  simply  the  exciting  cause. 

30.  And  what  is  the  Sensorium  ?  A  long  chapter 
would  be  required  to  state  the  various  opinions  which 
have  been  held  respecting  its  seat,  althougli  amid  all  the 
disputes  as  to  the  organ,  there  has  been  unanimity  as  to 
the  function,  which  is  that  of  converting  stimulations  into 
sensations.  I  cannot  pause  here  to  examine  the  contend- 
ing arguments,  but  must  content  myself  with  expounding 
the  opinion  I  hold,  namely,  that  the  Sensorium  is  the 
vjliole  of  the  sensitive  organism,  and  not  any  one  isolated 
portion  of  it.  When  light  falls  on  the  optic  organ,  or  air 
pulses  on  the  auditory  organ,  the  reaction  of  each  organ 
determines  the  s-pccific  character  of  the  sensation,  'but  no 
such  sensation  is  iMssihle  unless  there  he  a  reaction  of  the 
organism;  and  the  nature  of  the  product  will  of  course 
vary  with  tlie  varying  factors  which  co-operate — a  sim- 
ple organism,  a  truncated  organism,  an  exhausted  or  oth- 
erwise occupied  organism,  will  react  differently  from  a 
complex,  a  normal,  or  an  unoccupied  organism.  Detach 
the  optic  organ  with  its  centre  from  the  rest  of  the  organ- 
ism, and  no  normal  sensation  of  Sight  will  result  from  its 
stimulation  ;  and  in  a  lesser  degree  this  is  equally  true  of 
a  stinmlation  of  the  optic  organ  when  the  sensorium  is 
exhausted,  or  powerfully  affected  by  other  stimuli.  Be- 
cause of  the  great  importance  of  the  cerebrum,  and  its 
I)redominance  in  the  nervous  system,  it  has  been  supposed 
to  constitute  the  whole  of  the  sensorium,  in  sj^ite  of  the 
evidence  of  varied  Sensibility  after  the  cerebrum  has  been 
removed.  I  do  not  wish  to  underrate  tlie  cerebral  impor- 
tance (see  p.  16G),  yet  I  must  say  that  the  modern  phrase 
cerebration,  when  employed  as  more  than  a  shorthand  ex- 
pression of  the  complex  processes  which  a  cerebral  pro- 
cess initiates,  and  when  taken  as  the  objective  equivalent 


498  THE   PHYSICAL  BASIS   OF   MIND. 

of  Consciousness  or  of  Thought,  seems  to  me  not  more 
justifiable  than  to  speak  of  Combustion  as  the  equivalent 
of  Kailway  Transport.  The  railway  wagons  will  not  move 
unless  the  fuel  which  supplies  the  boiler  be  ignited ;  the 
organism  will  not  think  unless  the  cerebrum  excites  this 
peculiar  mode  of  Sensibility  by  its  action  on  the  organs. 
It  is  the  ma7i,  and  not  the  brain,  that  thinJcs :  it  is  the 
organism  as  a  whole,  and  not  one  organ,  that  feels  and 
acts. 

31.  Consciousness,  or  Sensation,  is  a  complex  product 
not  to  be  recognized  in  any  one  of  its  factors.  Cerebral 
processes  and  spinal  processes  are  the  elements  we  analyti- 
cally separate,  as  muscular  contractions  are  the  elements 
of  limb-movements.  The  synthetic  unity  of  these  ele- 
ments is  a  reflex ;  this  we  analytically  decompose  into  a 
sensation  and  a  movement;  and  then  we  speak  of  sensation 
as  the  reaction  of  the  sensory  organ,  the  movement  as  the 
reaction  of  the  muscular  organ.  By  a  similar  procedure 
we  separate  the  stimulation  of  a  sensory  nerve  from  the 
reaction  of  the  sensory  organ,  and  that  from  the  reaction 
of  the  sensorium  ;  and  in  this  way  we  may  come  to  regard 
Cerebration  as  Thought.  But  those  who  employ  this  arti- 
fice should  remember  that  the  organism  is  not  an  assem- 
blage of  organs,  made  up  of  parts  put  together  like  a 
machine.  The  organs  are  differentiations  of  the  organism, 
each  evolved  from  those  which  preceded  it,  all  sharing  in 
a  common  activity,  all  wi^cr-dependent. 

32.  That  co-operation  of  the  Personality  which  is  con- 
spicuous in  conscious  actions  is  also  inductively  to  be 
inferred  in  sub-conscious  and  unconscious  actions.  We 
know  that  a  man  reacts  on  an  impression  according  to  his 
physical  and  mental  state  at  the  moment  —  that  through 
his  individuality  he  feels  differently,  and  thinks  differ- 
ently from  other  men,  and  from  himself  at  other  epochs, 
and  in  other  states.     Because  he  resembles  other  men  in 


THE  REFLEX   THEORY.  499 

many  and  essential  points  we  conclude  that  he  will 
resemble  them  in  all;  but  observation  proves  this  con- 
clusion to  be  precipitate.  Other  men  see  a  blue  color 
in  the  sky,  or  feel  awe  at  sight  of  the  setting  sun ;  but 
he  has  perhaps  not  learned  to  discriminate  this  sensation, 
is  not  conscious  of  the  blue ;  nor  has  he  learned  to  feel 
awe  at  the  setting  sun.  Why  —  having  normally  con- 
structed eyes  —  does  he  not  see  the  blue  of  the  sky  ? 
For  the  same  reason  that  a  dog,  or  an  infant,  fails  to  see 
it.  The  color  has  no  interest  for  him  (and  all  cognition  isi/ 
primarily  emotion),  nor  has  this  want  of  personal  interest 
been  rectified  from  an  impersonal  source :  he  has  never 
been  taught  to  distinguish  the  color  of  the  sky ;  and  his 
eye  wanders  over  it  with  the  indifferent  gaze  with  which 
a  savage  would  regard  a  Greek  codex. 

33.  The  point  here  insisted  on,  namely,  that  every 
reaction  on  an  impression  is  indirectly  the  reaction  of 
the  whole  organism,  and  that  no  organ  detached  from  the 
organism  has  more  significance  than  a  word  detached  from 
a  sentence,  is  of  far-reaching  importance,  and  peculiarly 
worthy  of  attention  in  considering  the  Eeflex  Theory, 
because  almost  all  the  evidence  urged  in  support  of  that 
theory  presupposes  the  legitimacy  of  concluding  what 
takes  place  in  the  organism  from  what  is  observed  in  an 
organ  detached  from  its  normal  connections.  No  experi- 
mental proof  is  necessary  to  show  that  many  actions  take 
place  unconsciously ;  the  fact  is  undisputed.  But  does 
unconsciously  mean  insentiently  ?  It  is  certain  that  the 
unconscious  actions  take  place  in  a  sentient  organism,  and 
involve  organic  processes  of  the  same  order  as  the  actions 
which  are  conscious.  It  is  also  certain  that  many  sen- 
tient processes  take  place  unconsciously.  For  thousands 
of  years  men  used  their  eyes,  and  saw  as  their  descend- 
ants see,  yet  were  unconscious  of  the  blue  sky  and  green 
of  the  grass.    Were  their  visual  reactions  not  of  the  same 


500  THE   PHYSICAL   BASIS   OF   MIND. 

order  as  our  own  ?  So  far  as  the  optic  apparatus  is  con- 
cerned, there  cannot  be  a  doubt  on  the  point ;  yet  in  them 
the  sensorium  having  a  somewhat  different  disposition  — 
the  neural  elements  being  ditferently  combined  —  their 
reactions  correspondingly  differed.  Tliey  too  had  optical 
Sensibility,  and  visual  sensations ;  but  they  did  not  feel 
precisely  what  we  feel. 

34.  I  have  chosen  these  somewhat  remote  illustrations 
for  the  sake  of  their  psychological  interest ;  but  I  might 
have  confined  myself  to  more  familiar  examples.  Thus 
the  contents  of  the  consciousness  of  a  man  born  blind 
cannot  be  the  same  as  the  contents  of  one  who  has  had 
visual  experiences,  which  wiU  enter  into  the  complex  of 
every  conscious  state,  because  the  visual  organs  will  have 
affected  his  sensorium;  nevertheless  in  the  organism  of 
the  blind  man  there  are  conditions  so  similar  to  those 
of  other  men,  and  his  experiences  will  have  been  so  simi- 
lar, that  in  spite  of  the  modifications  due  to  the  absence 
of  visual  experiences,  his  consciousness  will  in  the  main 
resemble  theirs.  But  now  let  us  in  imagination  pursue 
this  kind  of  modificatiou,  let  us  take  away  hearing,  taste, 
and  smell,  and  we  shall  have  proportionately  simplified 
the  contents  of  consciousness  —  the  reactions  of  the  sen- 
sorium—  in  thus  simplifying  the  organism.  There  still 
will  remain  Touch,  Temperature,  Pain,  and  the  Systemic 
Sensations.  There  will  still  remain  an  organism  to  react 
on  impressions.  So  long  as  there  is  a  living  organism, 
liowever  truncated,  there  is  a  sentient  mechanism.  When 
tlie  brain  has  been  removed,  the  removal  causes  both  a 
disturbance  of  function  and  a  loss  of  function ;  the  mech- 
anism has  been  seriously  interfered  with ;  yet  all  those 
parts  of  the  mechanism  which  still  co-operate  manifest 
their  physiological  aptitudes.  The  animal  can  live  with- 
out its  brain,  ergo  it  can  feel  without  its  brain.  Observa- 
tion proves  this,  for  it  discovers  the   brainless  animal 


THE   REFLEX  THEORY.  501 

manifesting  various  sensibilities,  and  combining  various 
movements.  Tlie  vision  of  the  brainless  animal  is  greatly 
impaired,  but  it  nevertheless  persists.  The  intelligence  is 
greatly  impaired,  the  spontaneity  is  reduced  to  a  mini- 
mum ;  but  still  both  intelligence  and  spontaneity  are 
manifested. 

35.  The  physiologist  has  only  two  conclusions  open  to 
him.  Either  he  holds  Sensation  to  be  a  ijropcrtij  of  nerve- 
tissue  —  and  in  that  case  he  must  assign  it  to  the  spinal 
cord  as  to  the  brain ;  or  else  he  holds  Sensation  to  be  a 
function  of  an  organ  —  and  in  that  case,  although  ana- 
lytically he  may  decompose  the  organism  into  separate 
organs,  assigning  special  sensations  to  the  reactions  of 
each,  he  must  still  admit  that  in  reality  these  organs  only 
yield  sensations  as  component  parts  of  the  organism. 
The  notion  of  a  separate  organ,  such  as  the  brain,  being 
the  exclusive  seat  of  sensation  is  thus  seen  to  be  unten- 
able. 

In  popular  phrase,  "it  is  not  the  eye  which  sees,  but  the 
mind  behind  the  eye."  It  is  not  the  stimulus  which  is 
the  object  felt  —  it  is  the  change  in  consciousness  —  the 
reaction  of  the  sensorium.  No  one  would  propound  the 
absurdity  that  the  retinal  cells  sec,  or  the  auditory  cells 
hear  (although  by  a  conventional  ellipsis  these  cells  are 
said  to  be  "  percipient "  of  colors  and  sounds),  yet  many 
writers  have  no  hesitation  in  asserting  that  the  cerebral 
cells  are  the  seats  of  these  and  all  other  sensations.  In  a 
hundred  treatises  may  be  read  the  most  precise  descrip- 
tion of  the  transformation  of  molecular  changes  in  the 
retinal  cells  into  molecular  changes  in  tlie  cerebral  cells, 
where,  it  is  said,  "  we  know  that  the  stimulations  become 
sensations."  Now  who  knows  this  ?  How  can  it  be 
known  ?  Nay,  who,  on  reflection,  fails  to  see  tliat  this  can- 
not be  so  ?  If  a  sensation  of  sight  were  not  much  viorc 
tlian  a  molecular  change  in  the  cerebrum  stimulated  by  a 


502  THE   PHYSICAL   BASIS   OF   MIND. 

molecular  change  in  the  optic  tract,  three  conclusions  woulil 
follow,  each  of  which  is  demonstrably  erroneous  :  — 

I.  The  cerebrum  in  a  decapitated  animal  would  respond 
by  a  sensation  of  sight  to  a  retinal  stimulation. 

II.  The  animal  deprived  of  its  cerebrum  could  not  re- 
spond by  a  sensation  of  sight  to  a  retinal  stimulation. 

III.  The  same  retinal  stimulation  would  always  pro- 
duce the  same  cerebral  process  and  the  same  sensation ; 
whereas  the  sensation  depends  on  the  condition  of  the 
sensorium  at  the  time. 

36.  The  diflerence  between  the  Eeflex  Theor}^  and  that 
here  upheld  is  important  in  its  general  relations,  and  yet 
turns  on  a  point  which  may  easily  appear  insignificant. 
The  Eeflex  Theory  asserts  that  when  a  sensory  nerve  is 
stimulated,  the  excitation  of  the  centre  may  either  sub- 
divide into  two  waves,  one  of  which  passes  directly  to  the 
brain  and  there  awakens  sensation,  the  other  passes  over 
to  the  motor-roots  and  causes  muscular  contractions ;  or,  in- 
stead of  thus  subdividing,  the  wave  may  pass  at  once  to  the 
motor-nerves,  and  then  there  is  movement  without  sensa- 
tion. This  is  obviously  a  restatement  in  anatomical  terms 
of  the  observed  fact  that  some  reflexes  take  place  con- 
sciously and  some  unconsciously.  But  what  evidence  is 
there  for  this  anatomical  statement  ?  "We  have  seen  that 
there  is  none.  According  to  all  we  actually  know,  and 
reasonably  infer,  the  continuity  of  tissue  and  the  irradia- 
tion of  excitation  are  such  that  the  stimulus  wave  must 
always  affect  the  whole  system,  so  that  brain  and  cord 
being  structurally  united,  their  reactions  must  co-operate 
with  varying  energy  dependent  on  their  statical  conditions 
at  the  time.* 

*  The  idea  of  a  fixed  anatomical  mechanism  for  reflexion,  such  as  that 
of  an  excito-motory  system,  is  completely  refuted  by  the  fact  that  the  gray 
substance  may  anywhere  be  cut  away,  and  yet  so  long  as  a  small  bridge 
of  gray  substance  remains  the  stimulation  will  be  propagated  through  it. 


THE   REFLEX  THEORY.  503 

37.  The  physiological  fact  that  the  irradiation  is  re- 
stricted to  certain  paths,  and  therefore  only  certain  por- 
tions of  the  whole  system  are  excited  to  discharge  —  the 
fact  that  stimulation  takes  effect  along  the  lines  of  least 
resistance  —  is  that  which  gives  the  Keflex  Theory  its 
plausible  aspect.  But  this  fact  of  restriction  is  not  de- 
pendent on  an  anatomical  disposition  of  structure,  it  is, 
as  we  have  already  seen  (Problem  II.  §  166),  dependent 
on  a  fluctuating  physiological  disposition  —  a  temporary 
statical  condition  of  the  centres.  And  it  enables  us  to 
understand  wliy  the  reflex  action  which  is  at  one  moment 
a  distinctly  conscious  or  even  a  volitional  action,  is  at 
another  sub-conscious  or  unconscious.  When  an  object  is 
placed  in  the  hand  of  an  infant  the  fingers  close  over  it 
by  a  simple  reflex.  This  having  also  been  observed  in  the 
case  of  an  infant  born  without  a  brain,*  one  might  inter- 
pret it  as  normally  taking  place  without  brain  co-opera- 
tion, were  there  not  good  grounds  for  concluding  that 
normally  the  brain  must  co-operate.  Thus  if  the  object 
be  placed  in  the  hand  of  a  boy,  or  a  man,  the  fingers  will 
close,  or  not  close — not  according  to  an  anatomical  mech- 
anism, but  according  to  a  physiological  condition :  if  the 
attention  preoccupy  his  sensorium  elsewhere,  his  fingers 

The  idea  of  a  fixed  pathway  is  also  refuted  by  the  fact  of  the  variations 
in  the  reflex  responses,  and  the  necessary  irradiation  even  for  very  simple 
reflexes.  Take,  for  example,  that  of  breathing.  An  irritation  of  the 
bronchial  filaments  is  transmitted  by  the  pneumogastric  to  its  centre  in 
the  medulla  oblongata  ;  from  this,  however,  it  is  immediately  irradiated 
downwards  to  the  cervical  and  dorsal  regions,  which  innervate  the 
muscles  of  chest  and  diaphragm,  and  upwards  to  the  brain,  whether  the 
stimulation  awaken  consciousness  or  not.  One  may  say,  indeed,  that 
inasmuch  as  under  normal  conditions  tlie  bronchial  irritation  always 
causes  a  movement  of  a  particular  group  of  muscles,  there  is  to  this  ex- 
tent a  fixed  pathway  of  discliarge ;  but,  as  I  have  formerly  explained,  this 
is  only  an  expression  of  the  particular  tcmsion  of  particular  centres,  and 
is  variable  with  that  tension  ;  the  other  centres  are  also  aff'ected,  even 
when  tlioy  are  not  excited  to  discharge. 

*  Lallema.nd,  llec/ierc/ies  sar  i Enolphalc,  IlL  310. 


504  THE   PHYSICAL   BASIS   OF   MIND. 

will  probably  close,  probably  not;  if  his  sensorium  be 
directed  towards  the  object,  either  by  the  urgency  of  the 
sensitive  impression,  or  by  some  one's  pointing  to  the  ob- 
ject, the  fingers  will  close  or  not  close,  just  as  he  chooses 
—  perhaps  tlie  hand  will  be  suddenly  drawn  away.  The 
centre  of  innervation  for  the  fingers  is  in  the  cord,  and 
from  this  comes  the  final  discharge  of  the  sensitive  stimu- 
lation ;  but  the  neural  j)rocesses  which  jjreceded  this  dis- 
charge, and  were  consequent  on  the  stimulation,  were  in 
each  case  somewhat  different.  In  each  case  the  impres- 
sion on  the  skin  was  carried  to  the  cord,  and  thence 
irradiated  throughout  the  continuous  neural  axis,  re- 
stricted to  certain  paths  by  the  resistance  it  met  with, 
but  blending  with  waves  of  simultaneous  excitations  from 
other  sources,  the  final  discharge  being  the  resultant  of 
these  component  forces.  We  may  suppose  the  brain  to 
be  the  seat  of  consciousness,  and  yet  not  conclude  that 
the  brain  was  unaffected  because  the  fingers  closed  un- 
consciously ;  any  more  than  we  conclude  that  the  retina 
of  the  unoccupied  eye  is  unaffected  by  light  when  with 
the  other  we  are  looking  through  a  microscope,  and  only 
see  objects  with  this  eye  —  though  directly  we  attend  to 
the  impressions  on  the  other  eye  we  see  the  objects  which 
before  were  unseen.  We  know  that  the  muscles  of  the 
back  are  all  involved  in  walking,  standing,  etc.,  but  we 
are  seldom  conscious  of  their  co-operation  till  rheumatism 
or  lumbago  makes  us  painfully  alive  to  it. 

38.  The  two  main  positions  of  the  Eeflex  Theory  are, 
1°,  that  reflex  actions  take  place  without  brain  co-opera- 
tion, —  as  proved  by  observation  of  decapitated  animals ; 
2°,  that  they  take  place  without  brain  co-operation,  —  as 
proved  by  our  being  unconscious  of  them. 

To  these  the  answers  are :  1°.  The  proof  drawn  from 
observation  of  decapitated  animals  is  defective,  because 
the  conditions  of  the  organism  are  then  abnormal  —  there 


THE    REFLEX    THEORY.  505 

is  a  disturbance  of  the  mechanism,  and  a  loss  of  some  of 
its  components.  The  fact  that  a  reflex  occurs  in  the 
absence  of  the  brain  is  no  proof  that  reflexes  when  the 
brain  is  present  occur  without  its  participation.  2°.  The 
absence  of  consciousness  cannot  be  accepted  as  proof  of 
the  brain  not  being  in  action,  because  much  brain-work 
is  known  to  pass  unconsciously,  and  there  are  cerebral  re- 
flexes which  have  the  same  characters  as  spinal  reflexes. 

39.  A  prick  on  the  great  toe  traverses  the  whole  length 
of  the  spinal  axis  with  effects  manifested  in  various  or- 
gans—  the  muscles  of  the  limb,  the  heart,  the  chest,  the 
eyes,  etc.  The  leg  is  withdrawn,  the  heart  momently 
arrested,  the  eyes  turned  towards  the  source  of  irritation, 
the  thoughts  directed  towards  relief.  These  effects  can 
be  observed  —  there  are  others  which  lie  beyond  our  ob- 
servation, and  can  only  be  revealed  by  delicate  experi- 
mental tests.  But  even  the  observable  effects  are  very 
fluctuating,  because  they  depend  on  fluctuating  condi- 
tions. All  we  can  say  is,  that  so  long  as  there  is  con- 
tinuity of  structure,  there  must  be  continuity  of  excita- 
tion; and  the  brain  structurally  connected  with  the  centre 
of  a  sensory  impression,  must  necessarily  co-operate  more 
or  less  in  the  reactions  of  that  centre.  In  other  words, 
the  "brain,  although  not  the  exclusive  seat  of  sensation, 
plays  a  part  in  every  particular  sensation,  so  long  as  it 
forms  a  part  of  the  stimulated  organism. 

40.  This  view  being  so  widely  opposed  to  the  views 
current  in  physiological  schools,  I  was  gratified  to  find 
Dr.  Crichton  Browne  led  by  his  researches  to  a  conclu- 
sion not  unlike  it  in  essential  features.  In  his  essay  on 
the  Functions  of  the  Optic  Thalami*  (well  worthy  of 
attention  on  other  grounds)  he  says  :  "  Allowing  the  spi- 
nal cord  a  power  of  independent  action,  it  may  still  be 
that  it  generally  acts  reflexly  through,  or  in  association 

*   JFest  Riding  Lunatic  Asylum  Reports,  1875,  Vol.  V.  pp.  252,  sq. 
vol,.  III.  22 


506  THE   niYSICAL   BASIS   OF   MIND. 

with,  a  superior  centre.  The  sensorial  ganglia  can  un- 
doubtedly act  alone  in  a  reflex  manner,  but  they  almost 
invariably  consult  the  cerebrum  before  dealing  with  the 
impressions  which  they  receive ;  so  it  may  be  that  the 
spinal  cord,  though  capable  of  spontaneous  reaction,  may 
yet  commonly  refer  to  some  higher  seat  of  compound  co- 
ordination before  sending  forth  an  answer  to  any  message 
brought  to  it."  What  is  here  stated  as  a  possible  and 
occasional  process,  I  consider  to  be  a  necessary  and  uni- 
versal process.  Dr.  Browne  acutely  remarks  that  if  "what 
may  be  termed  the  encephalic  loop  were  an  integral  part 
of  every  reflex  act,  then  the  influence  of  an  intracranial 
lesion  in  checking  reflex  action  would  not  be  difficult  to 
understand" — and  we  may  add  the  notorious  influence 
of  the  brain  in  arresting  reflex  actions,  and  modifying 
them  by  the  will,  which  is  only  explicable  on  the  suppo- 
sition that  the  cerebral  and  spinal  centres  are  functionally 
associated.  Dr.  Browne  further  remarks :  "  In  experi- 
menting upon  myself  I  have  sometimes  thought  that 
when  the  toe  is  pricked  the  sensation  of  pain  actually 
precedes  the  movement  of  withdrawal ;  and  in  experi- 
menting upon  patients  with  sluggish  nervous  systems  I 
have  certainly  noticed  that  after  the  pricking  of  the  toe 
the  little  cry  of  pain  has  anticipated  the  muscular  con- 
tractions of  the  leg.  Now  this  cry  of  pain  is  a  secondary 
reflex  act  through  the  sensorial  centre  ;  it  is  the  result  of 
a  discharge  from  efferent  nerves  from  the  summit  of  what 
we  have  spoken  of  as  the  encephalic  loop  line ;  and  we 
should  certainly  not  expect  that  it  would  be  developed 
earlier  than  the  primary  reflexion  upon  the  motor  appa- 
ratus, unless  indeed  what  we  have  regarded  as  the  primary 
reflexion  really  itself  took  place  by  way  of  the  loop  line." 
41.  The  difference  between  a  voluntary  and  involun- 
tary act  is  not,  I  conceive,  that  in  the  one  case  the  brain 
co-operates  and  in  the  other  is  inactive,  but  that  while  in 


THE   KEFLEX   THEORY.  507 

both  the  brain  co-operates,  the  state  of  the  sensorium 
known  as  mental  prevision  or  ideal  stimulation,  is  present 
in  the  one,  and  absent  or  less  conspicuovis  in  the  other. 
So  likewise  the  difterence  between  a  normal  reflex  action 
accompanied,  and  the  same  action  unaccompanied  by  con- 
sciousness, is  not  that  the  brain  co-operates  in  the  one 
and  is  inactive  in  the  other,  but  that  the  state  of  the  sen- 
sorium is  somewhat  different  in  the  two  cases.  Move- 
ments Avhicli  originally  were  voluntary  and  difficult  of 
execution  —  accompanied  therefore  by  brain  co-operation 

—  become  by  frequent  repetition  automatic,  easy  of  ex- 
ecution, and  unconscious  —  they  are  then  said  to  de- 
pend on  the  direct  action  of  the  established  mechanism. 
Granted.  But  what  are  the  components  of  this  mechan- 
ism ?  Are  they  not  just  those  centres  and  organs  which 
at  first  effected  the  movements  ?  In  becoming  easy  and 
automatic,  the  movements  do  not  change  their  mechanism 

—  the  moving  organs  and  the  motor  conditions  remain 
what  they  were  ;  all  that  is  changed  is  the  degree  of  con- 
sciousness, i.  e.  the  state  of  the  sensorium  which  precedes 
and  succeeds  the  movement.  It  is  this  which  constitutes 
the  difficulty  of  the  question.  Some  readers  may  con- 
sider that  all  is  conceded  when  unconsciousness  is  admit- 
ted. But  this  is  not  so.  My  present  argument  is  the 
physiological  one  that  the  brain  co-operates  in  reflex 
actions  whenever  the  brain  is  structurally  united  with  the 
reflex  centres ;  the  psychological  question  as  to  whether 
consciousness  is  also  involved  in  this  brain  co-operation 
must  be  debated  on  otlier  grounds ;  and  we  have  already 
seen  that  consciousness  operates  in  gradations  of  infinite 
delicacy. 

Observe  a  man  performing  some  automatic  action,  sucli 
as  planing  a  deal  board,  or  cutting  out  a  pattern,  whicli 
lie  has  done  so  often  that  he  is  now  able  to  do  it  "  me- 
chanically."    It  is  certain  tliat  liis  brain  co-operates,  and 


508  THE   PHYSICAL   BASIS   OF   MIND. 

that  he  could  not  act  thus  with  an  injured  brain ;  yet 
he  is  said  to  act  unconsciously,  his  brain  occupied  else- 
where as  he  whistles,  talks  to  bystanders,  or  tliinks  of 
his  wife  and  children.  Yet  the  brain  is  acting  as  an  over- 
seer of  his  work,  attentive  to  every  stroke  of  the  plane, 
every  snip  of  the  scissors ;  and  this  becomes  evident 
directly  his  attention  is  otherwise  absorbed  by  an  inter- 
esting question  addressed  to  him,  or  an  interesting  object 
meeting  his  eye:  then  the  work  pauses,  his  hands  are 
arrested,  and  the  automatic  action  will  only  be  resumed 
when  his  attention  is  released  —  when  he  has  answered 
your  question,  or  satisfied  himself  about  the  object. 

42.  This  is  a  step  towards  understanding  the  co-opera- 
tion of  the  brain  even  in  those  connate  reflexes  which 
were  not  originally  voluntary  acts,  but  were  from  the 
first  organized  tendencies,  and  are  capable  of  being  real- 
ized in  the  absence  of  the  brain.  I  admit  that  it  is  diffi- 
cult to  find  proof  of  brain  co-operation  here,  though  I 
think  the  anatomical  and  physiological  evidence  render 
it  highly  probable.  But  distinct  proof  to  the  contrary 
would  not  suffice  for  the  Eeflex  Theory  —  would  not 
prove  that  reflex  actions  were  insentient  —  unless  there 
had  previously  been  proved  that  which  seems  to  me  con- 
tradicted by  the  clearest  and  most  massive  evidence, 
namely,  that  the  brain  is  the  sole  seat  of  sentience.  This 
contradictory  evidence  we  will  now  furnish. 


THE  KEFLEX  THEOKY.  509 


CHAPTEE    III. 

INDUCTIONS   FROM   PARTICULAR   OBSERVATIONS. 

43.  In  the  last  chapter  we  surveyed  the  deductive  evi- 
dence, from  which  the  conclusion  was  that  Eeflexion 
necessarily  involves  Sensibility,  but  not  necessarily  any 
one  particular  tnode  of  Sensibility,  such  as  Consciousness, 
Pain,  Discomfort,  Attention,  or  the  reaction  of  any  one 
of  the  special  Senses.  Although  each  or  all  of  these 
modes  may  be  involved  in  the  sensorial  process  which 
determines  a  reflex  act,  each  or  all  may  be  absent.  Such 
is  the  fact  of  observation.  This  fact  is  interpreted  on 
the  hypothesis  that  Reflexion  is  the  exclusive  property 
of  the  spinal  cord,  as  Sensation  is  of  the  brain.  When 
we  come  to  examine  the  evidence  for  this  hypothesis,  we 
find  it  to  move  in  a  circle :  the  brain  is  said  to  be  the 
exclusive  seat  of  sensation,  because  reflex  actions  can  be 
effected  after  its  removal ;  and  reflex  actions  are  said  to 
be  insentient  because  they  take  j)lace  in  the  absence  of 
the  brain. 

A  gentleman  was  one  day  stoutly  asserting  that  tliere 
were  no  gold-fields  except  in  Mexico  and  Peru.  A  nug- 
get, dug  up  in  California,  was  presented  to  him,  as  evi- 
dence against  his  positive  assertion.  He  was  not  in  the 
least  disconcerted.  "  This  metal,  sir,  is,  I  own,  extremely 
like  gold ;  and  you  tell  me  that  it  passes  as  such  in  the 
market,  having  been  declared  by  the  assayers  to  be  un- 
distinguishable  from  the  precious  metal.  All  this  I  will 
not  dispute.     Nevertheless,  the  metal   is  not  gold,  but 


510  THE   PHYSICAL  BASIS   OF  MIND. 

auruminium ;  it  cannot  be  gold,  because  gold  comes  only 
from  Mexico  and  Peru."  In  vain  was  he  informed  that 
the  geological  formation  was  similar  in  California  and 
Peru,  and  the  metals  similar ;  he  had  fixed  in  his  mind 
the  conclusion  tliat  gold  existed  onli/  in  Mexico  and  Pern : 
this  was  a  law  of  nature ;  he  had  no  reasons  to  give  why 
it  should  be  so;  but  such  had  been  the  admitted  fact 
for  many  years,  and  from  it  he  would  not  swerve.  He 
was  not  fond  of  new-fangled  notions,  which,  after  all, 
would  only  lead  us  back  to  the  exploded  errors  of  the 
past.  To  accept  the  statement  that  gold  was  to  be  found 
elsewhere  than  in  Mexico  and  Peru,  would  be  to  return 
to  the  opinion  of  the  ancients,  who  thought  there  was 
gold  in  the  upper  regions  of  Tartary  ! 

Sensation  is  not  tangible,  assayable,  like  gold.  We  can 
understand,  therefore,  that  the  very  men  who  would  make 
merry  with  the  auruminuim,  would  accept  easily  such  a 
phrase  as  "reflex  action."  The  decapitated  animal  de- 
fends itself  against  injury,  gets  out  of  the  way  of  annoy- 
ances, cleans  itself,  performs  many  of  its  ordinary  actions, 
but  is  said  to  do  these  things  without  that  Sensibility 
which,  if  its  head  were  on,  would  guide  tliem.  Even  be- 
fore the  Eeflex  Theory  was  invented  this  line  of  argu- 
ment was  used.  Gall,  referring  to  the  experiments  of 
Sue,  previously  noticed,  says  that  "  Sue  confounds  the 
effects  of  Irritability  with  those  of  Sensibility."*  Not 
gold,  dear  sir,  but  auruminium  ! 

44.  On  investigating  the  phenomena  we  soon  come 
upon  two  classes  which  must  cause  hesitation.  We  find 
that  the  brain  has  its  reflex  processes,  of  the  same  order 
as  those  of  the  cord ;  we  find  that  these  processes  may 
be  conscious  or  unconscious,  voluntary  or  involuntary ; 
so  that  we  can  no  longer  separate  brain  from  cord  on  the 
ground  of  Reflexion.     In  this  respect,  at  least,  the  two 

*  Gall  d  Spurzheim,  Anat.  ct  Physiol,  du  Systanc  Nerveux,  I.  83. 


THE   REFLEX   THEOEY.  511 

are  mechanisms  with  similar  powers.  Turning  now  to 
the  other  class  of  phenomena,  M'e  find  that  precisely  as 
the  brain  is  an  organ  of  Eeflexion,  the  cord  is  an  organ 
of  Sensation.  All  the  evidence  we  can  have,  from  which 
to  infer  the  presence  of  sensation,  is  furnished  by  the 
sensorial  processes  in  the  cord,  liemove  the  brain,  and 
the  animal  still  manifests  Sensibility,  and  this  in  degrees 
of  energy  and  complexity  proportional  to  the  mechanisms 
still  intact :  some  of  these  manifestations  have  the  char- 
acter of  volitional  actions,  some  of  automatic  actions, 
some  of  Memory,  Judgment,  and  selective  Adaptation. 
These  we  observe  not  indeed  with  the  energy  and  variety 
of  such  manifestations  when  the  brain  co-operates,  since 
the  disturbance  of  the  organism  which  is  the  consequence 
of  the  brain's  removal  —  or  the  meagTeness  of  the  organ- 
ism which  is  the  correlative  of  the  brain  never  having 
been  developed  —  must  of  course  involve  a  corresponding 
difference  in  the  observed  phenomena ;  but  the  point  here 
brought  forward  is  that  phenomena  of  the  same  order  are 
manifested  by  organisms  with  or  without  a  brain. 

45.  Let  us  go  seriatim  through  the  evidence  of  these 
two  classes :  — 

CEREBRAL   REFLEXES. 

While  Theory  separated  the  actions  of  the  cord  from 
those  of  the  brain  on  the  ground  of  their  being  at  times 
unconscious  and  involuntary,  Observation  disclosed  that 
this  distinction  could  not  be  maintained. 

This  step  was  taken  by  Dr.  Lay  cock  in  1840.  In  a 
striking  paper*  read  by  him  at  the  British  Association  in 
1844,  he  brought  together  the  evidence  on  which  his  view 
was  founded.  The  idea  has  been  adopted  and  illustrated 
in  the  writings  of  Dr.  Carpenter,  who  now  calls  the  action 
"  unconscious  cerebration," 

*  Piintcd  in  the  British  and  Foreign  Medical  Eevieir,  Jan.  ISl.'j. 


512  THE   niYSICAL   BASIS   OF   MIND. 

''  I  was  led  to  tliis  opinion,"  Dr.  Laycock  says  in  an- 
nouncing liis  view,  "  by  the  general  principle  that  the 
ganglia  within  the  cranium,  being  a  continuation  of  the 
spinal  cord,  must  necessarily  be  regulated  as  to  their  re- 
action on  external  agencies  by  laws  identical  with  those 
governing  tlie  spinal  ganglia  and  their  analogues  in  the 
lower  animals.  If,  therefore,  the  spinal  cord  is  a  centre 
of  reflexion,  the  brain  must  also  be  one."  It  is  a  matter 
of  regret  that  Dr.  Laycock  did  not  extend  this  principle, 
and  declare  that  whatever  was  true  of  the  properties  of 
the  cranial  centres  must  also  be  true  of  the  spinal  cen- 
tres ;  if  the  brain  have  Sensibility,  the  spinal  cord  must 
also  have  it. 

Dr.  Laycock  refers  to  the  curious  phenomena  of  Hydro- 
phobia in  proof  that  reflex  actions  may  be  excited  by  the 
optic  nerves,  or  by  a  mere  idea  of  water.  When  a  mirror 
was  presented  to  a  patient,  the  reflexion  of  the  light  act- 
ing on  liis  retina,  in  the  manner  of  a  reflexion  from  the 
surface  of  water,  produced  a  convulsive  sobbing,  as  in  the 
attempt  to  swallow  water,  and  the  patient  turned  aside 
his  head  with  expressions  of  terror.  Money  was  given 
him  to  induce  him  to  look  a  second  time,  but  before  he 
had  looked  a  minute  the  same  effect  w^as  produced. 

The  idea  of  water  excited  similar  convulsions.  Xo 
sooner  was  it  suggested  that  the  patient  should  swallow 
a  little  water  than  he  seemed  frightened,  and  began  to 
cry  out.  By  kindly  encouragements  he  was  brought  to 
express  his  willingness  to  drink,  but  the  sound  of  the 
Walter,  as  it  was  poured  out  again,  brought  on  convulsions. 
In  another  case,  "  on  our  proposing  to  him  to  drink,  he 
started  up,  and  recovered  his  breath  by  a  deep  convulsive 
inspiration.  On  being  urged  to  try,  he  took  a  cup  of 
M'ater  in  one  hand  and  a  spoon  in  the  other.  With  an 
expression  of  terror,  yet  with  great  resolution,  he  filled 
the  spoon  and  proceeded  to  carry  it  to  his  lips ;  but  be- 


THE   EEFLEX  THEORY,  513 

fore  it  reached  his  mouth  his  courage  forsook  hira,  and  he 
was  forced  to  desist.  He  repeatedly  renewed  the  attempt, 
but  with  no  more  success.  His  arm  became  rigid  and 
immovable  whenever  he  tried  to  raise  it  to  his  mouth, 
and  he  struggled  in  vain  against  this  spasmodic  resist- 
ance." 

In  1843  Griesinger — who  appears  to  have  known 
nothing  of  Dr.  Laycock's  paper  —  published  his  remark- 
ably suggestive  memoir  on  Psychical  Reflexes,*  in  which 
he  extends  the  principle  of  lieflexion  to  all  the  cerebro- 
spinal centres.  The  whole  course  of  subsequent  research 
has  confirmed  this  view ;  so  that  we  may  say  with  Lan- 
dry, "L'existence  du  pouvoir  reflexe  dans  I'encephale  ou 
dans  quelques  unes  de  ses  parties  etablit  une  nouvelle 
analosie  entre  le  centre  nerveux  crauien  et  la  moelle 
epiniere.f  Indeed  we  have  only  to  consider  the  Laughter 
which  follows  a  ludicrous  idea,  or  the  Terror  which  fol- 
lows a  suggestion  of  danger,  —  the  varying  and  involun- 
tary expression  of  Emotion,  —  and  the  curious  phenomena 
of  Imitation  and  Contagion,  —  to  see  how  large  a  place 
cerebral  reflexion  occupies. 

46.  The  existence  of  cerebral  reflexion  having  been 
thus  made  manifest.  Dr.  Carpenter  classed  all  reflex 
actions  under  three  heads :  1°,  the  excito-motor,  deter- 
mined by  the  spinal  cord ;  2°,  the  sensori-motor,  de- 
termined by  the  ganglia  at  the  base  of  the  brain ;  3°, 
ideo-motor,  determined  by  the  brain.  From  all  these 
Consciousness  is  absent.  From  the  first,  he  supposes 
►Sensation  to  be  absent.  As  an  artifice,  such  a  classifi- 
cation may  have  its  value,  but  it  is  physiologically  and 

*  Griesinger,  Abhandlungen,  1872.  The  first  volume  contains  a  re- 
))rint  of  this  memoir. 

t  Laxdrv,  TraiU  des  Pamlysics,  I.  55.     Conf.  Ziemssen,  Chorea  in 
the  Ilandbuch  dcr  specielhn  Pathologic,  Bd.  XII.  2,  p.  408.     And  Luys, 
Etudes  dc  physiol.  etpalhol.  cMbrales,  1874,  pp.  89-94. 
22* 


514  THE   PHYSICAL   BASIS   OF   MIND. 

psychologically  misleading.  It  sustains  the  hypothesis 
of  an  imaginary  excito-motor  mechanism.  It  restricts 
Sensibility  to  one  of  its  many  modes.  It  fails  altogether 
to  connect  Sensation  with  Tliought,  the  Logic  of  Feeling 
M'ith  the  Logic  of  Signs. 

47.  The  view  of  Sensibility  as  common  to  the  whole 
cerebro-spinal  axis  is  by  no  means  new.  Robert  Whytt 
maintained  it.  Prochaska  held  that  the  spinal  cord 
formed  the  greater  part  of  the  sensorium  commvMe;  and 
he  adduced,  in  proof,  the  familiar  facts  of  sensibility 
manifested  by  headless  animals.  The  next  writer  whom 
I  can  discover  to  have  held  this  opinion  is  J.  J.  Sue, — 
the  father  of  the  celebrated  French  romance-writer, — 
who,  in  1803,  conceived  tliat  his  experiments  proved  the 
spinal  cord  to  be  capable  of  replacing,  to  a  certain  ex- 
tent, the  functions  of  the  brain.*  Next  came  Legallois,t 
who  undertook  to  show,  by  a  series  of  experiments,  that 
the  principle  of  sensation  and  movement,  in  the  trunk 
and  extremities,  has  its  seat  in  the  spinal  cord.  The 
mere  division  of  the  cord,  he  said,  produces  "  the  aston- 
ishing result  of  an  animal,  in  which  the  head  and  the 
body  enjoy  separate  vitality,  the  head  living  as  if  the 
body  did  not  exist,  and  the  body  living  as  if  the  head  did 
not  exist.  Guinea-pigs,  after  decapitation,  seem  very  sen- 
sitive to  the  pain  caused  by  the  wound  in  the  neck ;  tliey 
alternately  carry  first  one  hind-leg  and  then  the  other,  to 
the  spot,  as  if  to  scratch  it.     Kittens  also  do  the  same." 

A  few  years  afterwards,  1817,  Dr.  Wilson  Philip  con- 
cluded that  "the  spinal  marrow  possesses  sensorial  power, 
as  appears  from  very  simple  experiments  " ;  but  he  held 

*  Sue,  Rccherches  PhilosopMques  siir  la  VitaliU  et  Ic  Galvanisme,  p.  9. 
He  was  not  consistent,  however,  but  adopted  Bichat's  opinion  respecting 
the  sensibility  of  the  viscera,  p.  68. 

t  Legallois,  Ex2)eriences  sur  h  principe  de  la  vie.  Published,  I  con- 
clude, in  1811;  the  edition  I  use  is  the  one  printed  in  the  Enq/dqpedie 
des  Sciences  Mcdicales,  IV. 


THE   KEFLEX   THEORY.  515 

the  brain  to  be  the  chief  source  of  sensorial  power.*  The 
following  year,  Lallemand  supported  this  opinion  by  the 
very  curious  phenomena  exhibited  by  infants  born  with- 
out brains :  these  infants  breathed,  swallowed,  sucked, 
squalled,  and  gave  very  unequivocal  signs  of  sensibility. 
The  value  of  such  observations  consists  in  disproving  the 
objection  frequently  urged  against  the  evidence  of  decapi- 
tated animals,  namely,  that  in  these  animals  the  spinal 
cord  preserves  the  remains  of  a  sensibility  endowed  by 
the  brain. 

Longet  here  places  an  observation  recorded  by  Beyer. 
A  new-born  infant,  whose  brain,  during  the  birth,  had 
been  completely  extirpated  (to  save  the  mother's  life), 
was  wrapped  in  a  towel,  and  placed  in  the  corner  of  the 
room,  as  a  lifeless  mass.  While  the  surgeon  Was  giving 
all  his  care  to  the  mother,  he  heard  with  horror  a  kind  of 
murmur  proceeding  from  the  spot  where  the  body  had 
been  placed.  In  three  minutes  a  distinct  cry  was  heard. 
The  towel  was  removed,  and,  to  the  surprise  of  all,  this 
brainless  infant  was  seen  struggling  with  rapid  movement 
of  its  arms  and  legs.  It  cried,  and  gave  other  signs  of 
sensibility  for  several  minutes.-j* 

In  1828  Calmeil  arrived  at  the  same  conclusion  as  that 
reached  by  Legallois,  A¥ilson  Philip,  and  Lallemand.  In- 
deed when,  in  1833,  the  Picflex  Theory  appeared,  this 
opinion  was  so  Ih-mly  rooted,  that  we  find  Mr.  Grainger 
combating  it  as  the  established  eiTor  of  the  day.  He 
takes  as  much  pains  to  show  that  physiologists  are  wrong 
in  attributing  sensation  to  the  spinal  cord,  as  I  am  here 
taking  to  show  that  they  were  right. :J:     "It  is,  indeed, 

*  WiL-soN  Philip,  Experimental  Inquiry  into  the  Laws  of  tlic  Vital 
Functions,  ]ip.  209,  210. 

t  Longet,  Trait6  dc  Physiolngic,  II.  lOo. 

X  He  cites  Cuvier,  Majendie,  Desmoulins,  aud  Mayo  as  maintaining 
this  error. 


516  THE   PHYSICAL   BASIS   OF   MIND. 

apparent,"  he  says,  "  that  the  whole  question  concerning 
the  truth  or  falsehood  of  the  theory  which  attributes  the 
reflex  power  to  the  spinal  cord  hinges  upon  the  correct- 
ness or  incorrectness  of  the  received  doctrines  respecting 
the  seat  of  sensation  and  volition ;  so  that  until  those 
doctrines  are  proved  to  be  false,  it  is  impossible  to  estab- 
lish the  hypothesis  of  Dr.  Hall."  * 

The  reader  is  requested  to  take  note  of  this,  because 
when  we  come  to  the  evidence  which  proves  the  spinal 
cord  to  be  a  centre  of  sensation,  we  shall  find  that  the 
only  ground  for  rejecting  that  evidence  is  the  assumed 
truth  of  the  Eeflex  Theory,  coupled  with  the  assumption 
of  the  brain  being  the  exclusive  seat  of  sensation. 
Whereas  if  the  evidence  proves  that  the  spinal  cord  is  a 
sensational  centre,  then  the  Eeflex  Theory  is  destroyed, 
and  cannot  be  urged  against  such  evidence. 

48.  Thus  many  of  the  facts  whicli  prove  the  sensa- 
tional function  of  the  spinal  cord  were  known,  and  even 
a  vague  conception  of  their  real  significance  was  general, 
until  the  Eeflex  Theory  came  to  explain  all  such  facts  as 
the  results  of  mechanical  adjustment,  and  of  a  new  ner- 
vous principle  called  "  Eeflexion."  For  many  years  this 
theory  has  reigned,  and  met  with  but  little  opposition. 
Yet  the  true  doctrine  has  not  wanted  defenders  in  Ger- 
many. ISTasse  f  denied  that  decapitated  animals  showed 
no  spontaneity ;  he  asserted  that  they  exhibited  clear 
signs  of  mental  activity.  Carus  sarcastically  pointed  out 
that  the  word  "  reflex  "  was  replacing  "  irritability,"  as  a 
key  to  unlock  all  puzzles ;  and  he  took  up  a  position 
which  is  very  similar  to  the  one  occupied  in  these  pages, 
namely,  that  the  spinal  cord  being  formed  of  gi'ay  matter 
as  well  as  of  fibres,  it  must  have  sensibility  and  power  of 
reacting  on  nervous  stimulus,  no  less  than  conductibility ; 

*  Graixger,  structure  and  Functions  of  tlie  Sjnnnl  Cord,  p.  66. 
+  Kasse,  Untcrs.  zur  Physiologic  und  Pathologic,  Vol.  II.  Part  2. 


THE   REFLEX  THEORY.  517 

that,  in  fact,  it  is  a  centre,  and  must  act  like  all  other 
nerve-centres.*  J.  W.  Arnold  opposed  the  Eeflex  Theory 
in  a  very  remarkable  little  work,  in  which  he  vindicates 
the  claim  of  the  spinal  cord  as  a  sensory  and  motor  cen- 
tre, although  denying  to  its  actions  any  volitional  char- 
acter.-f-  This  was  in  1844.  Eleven  years  elapsed  without 
any  further  opposition,  when  Edward  Pflliger,  in  1853, 
published  his  work  on  the  Sensorial  Functions  of  the 
spinal  cord.:]:  In  this  work  he  recurred  to  the  old  views 
of  Prochaska  and  Legallois ;  but  although  he  attacked 
ISIarshall  Hall  with  merciless  severity,  he  did  not  point 
out  the  fundamental  error  of  the  Pteflex  Theory,  which 
theory  he  seems  to  accept.  Nor  did  he  give  his  views 
that  philosophical  and  anatomical  basis  which  could  alone 
render  his  interpretations  acceptable.  Added  to  this,  the 
tone  of  asperity  in  which  his  work  was  written,  created 
some  prejudice  against  him ;  and  thus,  while  many  ad- 
mitted his  facts,  they  rejected  his  conclusions.§ 

In  1858  Professor  Owen  read  a  paper  of  mine  at  the 
Leeds  meeting  of  the  British  Association,  on  "  The  spinal 
cord  as  a  centre  of  Sensation  and  Volition,"  in  which  a 
rapid  indication  of  my  point  of  view,  and  an  account" of 
some  experiments  to  illustrate  it,  were  given  —  not,  I 
believe,  conclusive  to  any  of  the  audience.  Indeed,  the 
subject  was  too  vast  to  be  discussed  in  such  a  paper ;  and 
my  object  was  rather  to  excite  new  inquiry,  than  to  make 
converts  to  a  view  which  could  only  be  embraced  after  a 
thorough  reinvestigation  of  the  dominant  theories. 

In  1859  appeared  Schiff 's  work ;  ||  and  here  we  find  a 

♦  Caru.s,  System  der  Physiolofjie,  III.  101. 

t  J.  W.  Arnold,  Die  Lehrc  von  der  Eeflex- Function,  86. 

t  Pfl'uger,  Die  scnsorischen  Funclionen  des  Eilckenmarks  der  Wir- 
heUMere. 

§  Except  AuERBACH,  who  repeated  and  varied  the  experiments  ;  and 
FrsKE,  who  partially  adopted  the  conclusions  in  his  systematic  treatise 
on  rhvsiolog)-. 

Sc/MT,  Lfhrhuch  der  Pluisiulofjic,  208. 


518         THE  PHYSICAL  BASIS  OF  MIXD. 

large  space  allotted  to  the  discussion  of  Pfliiger's  doctrine. 
Schiff,  Avhose  immense  experience  as  an  experimentalist, 
and  whose  acuteness  and  caution  every  one  will  highly 
estimate,  frankly  pronounces  in  favor  of  the  sensational 
character  of  spinal  actions ;  but  he  denies  that  they  are 
volitional,  and  objects  strongly  to  the  introduction  of  any 
such  idea  as  that  of  "  psychical  activity."  He  thinks  it 
utterly  untenable  to  suppose  that  impressions  have  reac- 
tions in  the  brain  which  they  have  not  in  the  spinal 
cord :  —  if  one  has  sensibility,  the  other  must  have  it ; 
and  he  thinks  that,  so  far  from  the  actions  of  the  cord 
being  distinguishable  from  those  of  the  brain  by  the 
character  of  "  reflexion,"  and  depending  on  a  mechanical 
arrangement  —  all  actions,  cerebral  or  spinal,  are  reflex ; 
all  depend  on  a  mechanical  arrangement.* 

Since  that  time  there  has  been  the  remarkable  work  of 
Goltz,  so  often  cited  in  these  pages,!  and  his  subsequent 
experiments  on  dogs,  which  ( although  he  does  not  deci- 
sively adopt  the  views  of  Pfliiger )  furnish  ample  evidence 
that  sensation  and  vohtion  cannot  be  exclusively  localized 
in  the  brain. 

49.  Heubel's  interesting  experiments  %  show  that  a 
frog  may  be  thrown  into  a  state  of  profound  sleep  by  the 
withdrawal  of  all  external  stimulation,  and  in  this  state 
will  remain  lying  on  its  back  for  hours.  N'ow  this  posi- 
tion is  one  so  very  imcomfortable  that,  when  awake,  the 
frog  will  not  retain  it  a  moment,  if  free  to  turn  round ;  and 

*  Landry,  Traite  des  Paralysies,  1859,  maintains  that  the  cord  is  a 
centre  of  sensation,  and  that  there  is  in  it  a  faculty  analogous  to  the  per- 
ception and  judgment  of  the  brain.  Compare  pp.  163  et  sq.  and  305. 
He  also  cites  an  essay  by  Dr.  Paton  of  Edinburgh  ( Edinburgh  Medical 
Journal,  1846  ),  iA  which  the  sensational  and  volitional  claims  of  the 
spinal  cord  are  advanced. 

+  Goltz,  Beitrdge  zur  Lehre  von  den  Functionen  dcr  Nervcnccntren 
des  Frosches,  1869. 

J  Pfliiger  s  Archiv,  Bd,  XIV.  p.  158. 


THE   REFLEX   THEORY.  519 

Aviien  asleep,  a  prick  on  the  toe,  a  sudden  noise,  or  a  beam 
of  light  will  awaken  it,  causing  it  to  turn.  That  is  to 
say,  the  withdrawal  of  the  normal  stimuli  so  lowers  the 
sensibility  of  the  frog's  nerve-centres,  that  he  does  not 
feel  the  effects  of  the  unusual  position,  but  feels  them 
directly  the  centres  are  stimulated  into  activity.  All  this 
is  intelligible  enough  on  the  supposition  of  the  state  of 
sleep  being  dependent  on  a  lowering  of  the  cerebral 
activity.  But  what  shall  we  say  on  learning  that  pre- 
cisely the  same  phenomena  are  manifested  by  a  brainless 
frog  ?  Every  one  knows  tliat  the  brainless  frog  is  intol- 
erant of  lying  on  its  back,  and  immediately  turns  round, 
if  placed  on  it.  Yet  the  brainless  frog  may  be  thrown 
into  deep  sleep  by  the  same  exclusion  of  external  stimuli ; 
from  which  he  also  will  be  awakened  by  a  prick,  a  noise, 
or  a  beam  of  light ;  and  no  sooner  is  he  awakened  than 
he  at  once  turns  round.  Were  the  brainless  frog  inca- 
pable of  sensation,  a  prick  on  his  toe  would  cause  a 
simple  reflex  withdrawal  of  the  leg ;  but  this  is  not  the 
effect ;  on  the  contrary,  the  stimulus  excites  the  whole 
spinal  cord,  and  whatever  sensation  of  discomfort  may 
be  caused  by  the  abnormal  position  of  the  limbs  in  an 
uninjured  awakened  frog,  is  excited  in  the  brainless  frog. 

50.  I  need  not  swell  this  chapter  with  examples  of 
Sensibility  in  animals  deprived  of  the  brain  ;  many  have 
already  been  given,  and  any  text-book  of  Physiology  will 
supply  more.  No  one  disputes  the  observations,  only  the 
inference  that  these  manifestations  were  sentient :  they 
are  said  to  have  been  merely  mechanical  reflexes.  Tf, 
however,  we  can  detect  in  them  some  evidence  of  what  all 
recognize  as  peculiarly  characteristic  of  Mind,  the  mechan- 
ical interpretation  will  be  less  plausible. 

At  the  outset  the  reader  must  be  warned  against  exaji- 
gerating  and  distorting  the  beanng  of  my  remarks,  and 
must  not  suppose  that  I  disregard  the  vast  differences 


520  THE  niYSICAL   BASIS   OF  MIND. 

between  the  Logic  of  Signs  which  belongs  to  Thought, 
and  the  Logic  of  Feeling  which  belongs  to  Sensation,  nor 
suppose  that  I  look  upon  the  spinal  cord  as  a  mental 
organ  having  the  same  functions  as  the  brain.  All  that 
I  wish  to  establish  is  the  common  character  of  spinal  and 
cerebral  processes,  modified  as  each  is  by  the  character  of 
the  actions  initiated  by  the  process. 

51.   This  premised,  let  us  begin  with  the  evidence  of 

DISCEIMINATION. 

Although  this  process  is  usually  regarded  as  purely 
psychological,  it  must  obviously  have  its  physiological 
side ;  we  find  it  in  Sensation  as  in  Ideation,  and  may  ex- 
pect to  find  it  in  unconscious  as  in  conscious  processes  — 
in  a  word,  in  all  sensorial  processes  whatever.  Place  a 
bit  of  marble  on  your  tongue,  and  it  will  be  touched,  but 
not  tasted  :  the  sensations  of  contact  and  temperature  will 
excite  reflexes,  but  little  or  no  reflexes  from  parotid  and 
salivary  glands.  A  difference  in  sensation  has  a  corre- 
sponding difference  in  reflex  action ;  which  may  be  made 
evident  by  removing  the  tasteless  marble,  and  replacing 
it  by  a  pinch  of  carbonate  of  lime,  i.  e.  the  marble  in  an- 
other state  reduced  to  a  powder :  this  will  excite  a  sen- 
sation of  taste,  and  a  secretion  from  the  glands.  In  both 
cases  your  sentient  organism  was  affected,  but  it  reacted 
differently  because  the  difference  of  the  stimulation  was 
discriminated  :  consciously  or  unconsciously,  you  felt  dif- 
ferently. Again :  touch  the  back  of  your  mouth  with 
your  finger,  or  a  feather,  and  a  convulsive  contraction  of 
the  gullet  responds,  followed  by  vomiting,  if  the  excita- 
tion be  renewed.  Yet  these  same  nerves  and  muscles 
respond  by  the  totally  opposite  action  of  swallowing,  if 
instead  of  the  stimulation  coming  from  your  finger,  it 
come  from  the  pressure  of  food  or  drink. 


THE    REFLEX   THEOKY.  521 

Analogous  experiments  on  animals  without  their  brains 
yield  similar  results.*  The  salivary  secretion  and  the 
ordinary  reactions  of  Taste  are  provoked  by  sapid  sub- 
stances. Still  more  conclusive  are  the  observations  made 
on  a  dog  whose  spinal  cord  has  been  divided,  and  who 
therefore  according  to  the  reigning  ideas  is  incapable  of 
feeling  any  impression  made  on  parts  below  the  section. 
A  pencil  inserted  in  the  rectum  causes  a  reaction  of  the 
muscles  energetically  resisting  the  entrance  of  this  for- 
eign body ;  yet  tliis  rectum  so  sensitive  in  its  reaction 
on  the  stimulus  of  the  pencil,  responds  by  the  totally 
different  reaction  —  the  relaxation  of  the  muscles  —  on 
the  stimulus  of  faecal  matters. 

52.  "  This  is  all  mechanical,"  you  say  ?  Mechanical, 
no  doubt,  as  all  actions  are ;  but  the  question  here  is 
whether  among  the  conditions  of  the  mechanical  action 
Sensibility  has  a  place  ?  Tlie  answer  can  only  be  grounded 
on  induction.  The  actions  of  the  dog  are  analogous  to 
the  actions  which  you  know  were  sentient  in  yourself. 
There  was  in  both  a  discrimination,  in  both  a  correspond- 
ing reaction.  I  admit  that  what  is  here  called  "discrim- 
ination "  is  the  application  of  a  logical  term  to  a  mechan- 
ical process ;  I  admit  that  if  the  spinal  mechanism  is  • 
insentient,  the  fact  of  discrimination  may  still  be  mani- 
fested ;  but  I  conceive  that  the  many  and  coercive  grounds 
for  admitting  that  the  mechanism  is  sentient  gain  further 
support  in  the  evidence  of  discrimination.  Every  par- 
ticular sensation  has  its  corresponding  reaction ;  and  al- 
tliough  this  has  been  acquired  during  ancestral  or  indi- 
vidual experiences,  so  that  in  the  majority  of  cases  there 
is  no  consciousness  accompanying  tlie  operation,  this,  as 
we  have  seen,  is  not  a  valid  argument  against  the  ex- 
istence of  a  sensorial  process.  We  have  only  to  lower 
the  Sensibility  of  tlie  cord  l)y  ana3Sthetics,  or  to  jpreoccupy 

*  SeeProb.  II.  §183. 


522  THE  PHYSICAL   BASIS   OF  MIND. 

its  energies  by  some  other  excitation,  and  the  reaction 
fails. 

MEMOPwY. 

53.  "  But  discrimination,  if  not  a  purely  physical  pro- 
cess, implies  Memory  ?  "  No  doubt.  And  what  is  Mem- 
ory—  on  its  physiological  side  —  but  an  organized  ten- 
dency to  react  on  lines  previously  traversed  ?  As  Gries- 
inger  truly  says :  "  There  is  Memory  in  all  the  functions 
of  the  central  organs,  including  the  spinal  cord.  There 
is  one  for  reflex  actions,  no  less  than  for  sense-images, 
words,  and  ideas."  Gratiolet  makes  a  similar  assertion.* 
Indeed  if,  as  we  have  seen,  reflex  actions  are  partly  con- 
nate, and  partly  acquired,  it  is  obvious  that  the  second 
class  must  involve  that  very  reproduction  of  experiences, 
which  in  the  sphere  of  Intellect  is  called  Memory. 

There  is  assuredly  something  paradoxical  at  first  in 
this  application  of  the  terms  of  the  Logic  of  Signs,  yet 
the  psychologist  will  find  it  of  great  service.  But  if  the 
terms  discrimination  and  memory  be  objected  to,  they 
may  be  replaced  by  some  such  phrase  as  the  "  adaptation 
of  the  mechanism  to  varying  impulses."  On  its  objective 
side,  Discrimination  is  Neural  Grouping;  on  its  subjec- 
tive side,  it  is  Association  of  experiences. 

INSTINCT. 

54.  If  we  can  detect  evidences  of  Volition  and  Instinct 
in  the  absence  of  the  brain,  our  thesis  may  be  considered 
less  questionable.  And  such  evidence  there  is.  Goltz 
decapitated  a  male  frog  (in  the  pairing  season),  and  ob- 
served that  it  not  only  sought,  grasped,  and  energetically 

*  "  II  y  a  (lone  une  memoire  par  le  cerveau  et  une  memoire  par  I'au- 
tomate.  Tous  les  organes  ont  une  memoire  propre,  c'est  h  dire  une  ten- 
dance a  reproduire  les  series  d'actes  qu'ils  ont  plusieurs  fois  executes."  — 
Gratiolet,  Anat.  du  SysUme  Kcrvcux,  1857,  p.  464. 


THE  EEFLEX   THEORY.  523 

embraced  a  female,  but  could  always  discriminate  a  fe- 
male from  a  male.  Thus  when  a  male  frog  closely  re- 
sembling a  female  in  size  and  shape  was  presented  to 
this  decapitated  animal,  he  clasped  it,  but  rapidly  let  it 
go  again,  whereas  even  the  dead  body  of  a  female  was 
held  as  in  a  vice.  Goltz  tried  to  delude  this  brainless 
animal  in  various  ways,  always  in  vain.  Only  a  female 
would  be  held  in  his  embrace.  Goltz  then  presented  a 
female  in  a  reversed  position,  so  that  the  head  was  grasped 
by  the  male.  Xow  here,  had  there  been  simply  a  reflex 
machine,  incapable  of  sentient  discrimination,  the  clutched 
female  would  have  been  held  in  this  position,  just  like 
any  other  object  which  excited  the  reflex ;  there  would 
have  been  no  "  sense  of  incongruity,"  such  as  Goltz  no- 
ticed in  his  frog,  who  at  once  began  a  series  of  move- 
ments by  whicli  he  was  enabled,  without  letting  the  fe- 
male escape,  to  bring  her  into  the  proper  position.  To 
render  this  observation  still  more  significant,  I  may  add 
that  Goltz  did  not  find  all  male  frogs  act  thus  —  many 
relinquished  the  female  thus  improperly  presented  to 
them.  Such  phenomena  observed  in  frogs  possessing 
brains,  would  be  accepted  as  evidence  of  sexual  instinct 
and  volition. 

Further :  Goltz  removed  the  brain  from  a  frog,  which 
he  then  held  under  water,  gently  pressing  the  body  so  as 
to  drive  the  air  out  of  its  lungs ;  the  body  being  then 
heavier  than  the  water  sank  to  the  bottom,  where  it  re- 
mained motionless.  He  repeated  this  procedure  with  an- 
other frog,  not  brainless  but  blinded.  This  one  sank  also, 
but  in  a  few  minutes  rose  to  the  surface  to  breathe.  This 
difference  naturally  suggests  that  the  brainless  frog  was 
insensible  of  the  condition  which  in  the  otlier  caused  a 
movement  of  relief  The  one  felt  impending  suffocation, 
the  other  felt  nothing.  Such  was  the  interpretation  of 
a  German  friend  in  whose  presence  I  repeated  tlie  oxpcri- 


524  THE   PHYSICAL   BASIS   OF   MIND. 

ment.  But  I  had  been  instructed  by  Goltz,  and  bade 
my  friend  wait  awhile.  He  did  so,  and  saw  the  brainless 
frog  slowly  rise  to  the  surface  and  breathe  there  like  his 
blinded  companion.  So  that  the  only  difference  observ- 
able w^as  in  the  lessened  sensibility  of  the  brainless  frog. 

55.  But  Goltz  records  a  still  more  conclusive  case.  In 
a  large  vessel  of  water  he  inverted  a  glass  jar  also  con- 
taining water,  which  could  then  only  be  retained  in  the 
jar  by  atmospheric  pressure.  Through  the  neck  of  this 
inverted  jar  he  tlirust  a  blinded  frog,  not  having  pressed 
the  air  out  of  its  lungs.  It  rose  at  once  in  the  jar,  touch- 
incr  the  inverted  bottom  with  its  nose,  and  when  the 
necessity  of  fresh  air  was  felt,  the  frog  began  restlessly 
feeling  about  the  surface  of  its  prison  till  an  issue  was 
found  in  the  neck  of  the  jar,  through  which  it  dashed 
into  the  vessel,  and  at  once  rose  to  the  surface  of  the 
water  to  breathe.  In  this  observation  are  plainly  mani- 
fested the  stimulation  of  uneasy  sensation,  the  volition 
of  seeking  relief,  and  the  discrimination  of  it  when  found. 
If  this  frog  was  a  sentient  mechanism,  what  shall  we  say 
to  the  fact  that  a  brainless  frog  was  observed  to  go  through 
precisely  the  same  series  of  actions  ?  Goltz  pertinently 
remarks :  "  So  long  as  physiologists  satisfied  themselves 
that  the  brain  was  the  sole  organ  of  sensation,  it  was 
easy  to  declare  all  the  actions  of  the  brainless  animal 
to  be  merely  reflex.  But  now  we  must  ask  whether  the 
greater  part  of  these  actions  are  not  due  to  the  'power  of 
adaptation  in  the  central  organs,  and  are  therefore  to  be 
struck  out  of  the  class  of  simple  reflexes  ?  If  I  bind  one 
leg  of  a  brainless  frog  and  observe  that  he  not  only 
sees  an  obstacle,  but  crawls  aside  from  it,  I  must  regard 
these  movements  as  regulated  by  his  central  power  of 
adaptation ;  but  now  suppose  I  unbind  the  leg  and  re- 
move the  obstacle,  then  if  I  prick  the  frog  he  hops  for- 
ward.    Must  I   now  declare   this   hop  to  have   been  a 


THE   EEFLEX   THEORY.  525 

simple  reflex  ?     Not  at  all.     In  both  cases  the  physio- 
logical processes  have  been  similar." 

56.  There  are  no  doubt  readers  who  will  dismiss  all 
evidence  drawn  from  experiments  on  frogs,  as  irrelevant 
to  mammals  and  man.  Let  us  therefore  see  how  the 
evidence  stands  with  respect  to  animals  higher  in  the 
scale,  endowed  with  less  questional)le  mental  faculties. 
In  a  former  chapter  (Problem  II.  §  29)  we  recorded  the 
marked  results  of  removing  the  cerebral  hemispheres ; 
and  at  the  same  time  suggested  that  these  by  no  means 
justified  the  conclusion  usually  drawn  respecting  the 
hemisj)heres  as  the  exclusive  seat  of  sensation.  And  this 
on  two  grounds  :  First,  because  the  absence  of  some  sen- 
sitive phenomena  does  not  prevent  the  presence  of  others : 
the  mutilated  organism  is  still  capable  of  manifesting 
Sensibility  in  those  organs  which  remain  intact.  Sec- 
ondly, because  were  the  mutilation  followed  by  total  de- 
struction of  Sensibility,  this  would  not  prove  Sensibility 
in  the  normal  organism  to  have  its  seat  in  the  part  in- 
jured. If  the  removal  of  a  pin  will  destroy  the  chrono- 
metric  action  of  a  watch,  we  do  not  thence  infer  that  the 
chronometric  action  was  the  function  of  this  pin.  And 
this  objection  has  the  greater  force  when  we  remember 
that  one  hemisphere  may  be  removed  without  the  conse- 
quent loss  of  a  single  function,  and  both  may  be  removed 
without  the  loss  of  several  functions  usually  ascribed  to 
cerebral  influence.* 

*  To  ohviatc  misnnflorstandiiiff  let  mo  say  that,  unless  the  contrary  is 
specified,  I  use  the  term  Brain  throughout  this  argument  as  equivalent  to 
the  cerebral  hemispheres,  because  it  is  in  these  that  .sensation,  volition, 
and  consciousness  are  localized  by  the  generality  of  writers,  many  of 
whom,  indeed,  regard  the  cells  of  the  gray  matter  of  the  convolutions  as 
the  exclusive  seat  of  these  phenomena,  dividing  these  cells  into  sensa- 
tional, emotional,  and  intellectual.  There  are  physiologists  who  extend 
.sensation  to  the  cerebral  ganglia  and  gray  masses  of  the  medulla  obloii- 


526  THE  PHYSICAL  BASIS   OF  MIND. 

57.  Consider  the  analogous  effects  of  injuries  to  or  re- 
moval of  the  Cerebellum,  in  causing  disturbance  of  loco- 
motion, whence  the  conclusion  has  been  drawn  that  the 
Cerebellum  is  the  exclusive  organ  of  muscular  co-ordina- 
tion, in  spite  of  the  unquestionable  evidence  that  very 
many  muscular  co-ordinations  still  persist  after  this  organ 
is  removed.  What  is  the  part  played  by  tlie  Cerebellum 
I  do  not  pause  here  to  examine.*  I  only  say  that  the 
movements  of  swimming,  suckimi,  swallowing,  breathinir, 
crying,  micturition,  defecation,  etc.,  are  co-ordinated  as 
well  after  removal  of  the  Cerebellum  as  they  were  before, 
and  that  consequently  their  co-ordination  has  not  its  seat 
in  the  Cerebellum.  The  parallelism  is  obvious.  Ee- 
moval  of  the  Cerebrum  causes  a  disturbance  in  the  com- 
bination of  sensations,  and  the  execution  of  certain  sense- 
guided  actions,  but  causes  little  appreciable  disturbance 
in  others.  Eemoval  of  the  Cerebellum  causes  a  disturb- 
ance in  the  combination  of  certain  muscular  sensations, 
and  the  execution  of  certain  co-ordinated  actions,  with 
little  appreciable  disturbance  in  others. 

58.  So  little  have  the  facts  been  surveyed  and  esti- 
mated in  their  entirety  that  there  is  perhaps  no  subject 
on  which  physiologists  are  more  agreed  than  on  the  func- 
tion of  the  Cerebellum  being  that  of  co-ordination.  Yet 
consider  this  decisive  experiment.  I  etherized  three 
healthy  frogs,  from  one  I  removed  the  entire  cranial  cen- 
tres ;  from  another  I  removed  only  the  cerebellum ;  and, 

gata  ;  but  the  medulla  spinalis  is  so  clearly  continuous  with  the  medulla 
oblongata  that  there  is  a  glaring  inconsistency  in  excluding  sensation  from 
the  one  if  it  is  accorded  to  the  other ;  and  the  grounds  on  which  sensi- 
tive phenomena  are  admitted  in  the  absence  of  the  hemispheres,  force  us 
to  admit  analogous  phenomena  in  the  absence  of  the  ganglia  and  medulla 
oblongata :  in  each  case  the  phenomena  are  less  complex  and  varied  as 
the  mechanisms  become  less  complex. 

*  Compare  LussANA  e  Lemoigne,  Fisiologia  del  ccntrL  encefalici,  1871, 
II.  239,  240,  330. 


THE   REFLEX   THEORY.  527 

leaving  the  third  in  possession  of  an  intact  encephalon,  I 
made  two  sections  of  the  posterior  columns  of  the  spinal 
cord.  The  two  first  hopped,  swam,  used  their  legs  in  de- 
fence, and  exhibited  a  variety  of  muscular  co-ordinations, 
although  in  both  the  supposed  organ  of  co-ordination  was 
absent.  Whereas  the  third,  which  had  this  organ  intact, 
and  was  capable  of  moving  each  limb  separately,  and 
each  pair  of  limbs  separately,  was  utterly  incapable  of 
moving  all  four  simultaneously.  Why  was  this  ?  Obvi- 
ously because  in  the  first  two  frogs  the  motor  mechanism 
remained  intact,  and  only  the  cerebral  and  cerebellar  in- 
fiuence  was  removed ;  in  the  third  frog  the  sensory  part 
of  the  motor  mechanism  had  been  divided,  and  no  com- 
bination of  the  limbs  was  possible. 

59.  Physiological  induction  agrees  witli  anatomical  in- 
duction in  assigning  to  the  cerebrum  and  cerebelhun  the 
office  of  incitation  and  regulation  rather  than  of  innerva- 
tion ;  for,  as  we  have  seen,  no  nerve  issues  directly  from 
them  (Problem  II.  §  7).  Consequently  the  effects  of  in- 
juries to  these  centres  are  losses  of  spontaneity  and  of 
complexity  in  the  manifestations.  Inasmuch  as  in  the 
intact  organism  all  sensory  impressions  are  propagated 
throughout  the  nervous  centres,  the  reactions  of  these 
highest  centres  will  enter  into  the  complex  of  every  ad- 
justed movement;  so  the  abolition  of  these  centres  will 
be  the  dropping  of  a  link  in  the  chain,  the  abolition  of  a 
special  element  in  tlie  conii)lex  group.  The  organs  which 
are  still  intact  will  react,  each  in  its  own  way,  on  being 
stimulated ;  but  the  reaction  will  be  without  the  modi- 
fying influence  of  the  absent  centres.  For  instance,  the 
retinal  stimulation  from  a  luminous  impression  normally 
calls  up  a  cluster  of  associated  feelings  derived  originally 
from  other  senses,  and  a  perception  of  the  object  is  asso- 
ciated with  emotions  of  desire,  terror,  etc.,  according  to 
the  past  history  of  the  organism,  and  its  organized  reac- 


528  THE  PHYSICAL  BASIS   OF  MIND. 

tions,  due  to  hereditary  or  acquired  experiences.  It  is 
these  which  form  tlie  comjilex  feeling  discharged  in  the 
particular  movement  of  prehension,  or  flight,  llemove  the 
brain,  and  there  can  be  no  longer  this  cluster  of  associated 
neural  groups  excited ;  there  will  be  therefore  no  emo- 
tion, simply  the  visual  sensation,  and  such  a  movement 
as  is  directly  associated  with  it.  The  brainless  dog  moans 
when  hurt,  it  does  not  bark  at  the  cat  which  it  neverthe- 
less sees,  and  avoids  as  a  mere  obstacle  in  its  path ;  the 
cat  will  cry,  it  will  not  mew.  The  present  pain  moves 
the  vocal  organs,  but  does  not  revive  associated  experi- 
ences. All  those  combinations  by  which  a  series  of 
dependent  actions  result  from  a  single  stimulation  are 
frustrated  when  the  mechanism  is  disturbed,  so  that  the 
mutilated  animal  can  no  longer  recognize  its  prey  or  its 
enemy,  to  feed  on  the  one  and  fly  from  the  other ;  no 
longer  builds  its  habitation,  or  rears  its  offspring.  It  can 
still  live,  feed,  sleep,  move,  and  defend  itself  against  pres- 
ent discomfort ;  it  cannot  find  its  food,  or  protect  itself 
against  prospective  discomfort.  We  must  supply  the 
place  of  its  Intelligence.  We  must  give  it  the  food,  and 
protect  it  from  injuries. 

There  is  therefore  ample  evidence  to  show  that  what  is 
specially  known  as  Intelligence  is  very  imperfect  after 
the  cerebral  influence  has  been  abolished ;  but  this  does 
not  prove  the  Cerebrum  to  be  the  exclusive  seat  of  Intel- 
ligence, it  only  proves  it  to  be  an  indispensable  factor  in 
a  complex  of  factors.  Still  less  does  it  prove  the  Cere- 
brum to  be  the  exclusive  seat  of  Sensation,  Instinct,  Voli- 
tion ;  for  these  may  be  manifested  after  its  removal, 
although  of  course  even  these  will  be  impaired  by  the 
loss  of  one  factor. 

60.  And  here  an  objection  must  be  anticipated.  In 
spite  of  the  familiar  experience  that  one  mode  of  Sensi- 
bility may  be  destroyed  without  involving  the  destruction 


THE  KEFLEX   THEORY.  529 

of  other  modes,  there  is  a  general  belief —  derived  from  a 
mistaken  conception  of  what  is  really  represented  by  the 
unity  of  Consciousness — that  Consciousness  disappears 
altogether  when  it  disapjDears  at  all ;  and  hence,  since 
Sensation  is  supposed  to  imply  Consciousness,  it  also 
cannot  be  divisible,  but  must  vanish  altogether  if  it  van- 
ish at  all.  The  first  answer  is  that  Sensation  as  an  ab- 
straction is  neither  divisible  nor  indivisible ;  but  as  a 
generabzed  expression  of  concrete  sensorial  processes  it  is 
reducible  to  these  processes,  and  divisible  as  they  are- 
No  one  doubts  that  we  may  lose  a  whole  class  of  special 
sensations  —  sight,  hearing,  pain,  temperature,  etc.  —  yet 
retain  all  the  others.  No  one  doubts  that  we  may  lose  a 
whole  class  of  registered  experiences  —  forget  a  language, 
or  lose  memory  of  places  so  familiar  as  the  streets  of 
the  small  town  we  inhabit,  or  of  faces  so  familiar  as  those 
of  friends  and  relatives,  while  the  names  of  these  streets 
and  friends  are  still  remembered  when  the  sounds  are 
lieard.  Yet  sensation  and  intelligence  are  not  wholly  lost. 
The  mind  is  still  erect  amid  these  ruins.* 

61.  This  premised,  let  ns  consider  the  experimental 
evidence.  Flourens  declares  that  when  he  removed  the 
whole  of  the  Cerebrum  from  pigeons  and  fowls,  they  lost 
all  sensation,  all  perception,  all  instinct,  and  all  volition. 
They  lived  perfectly  well  for  months  after  the  operation, 
if  the  food  were  placed  in  their  mouths ;  but  they  never 
sought  their  food ;  they  never  took  it,  even  when  their 
l)eaks  were  plunged  into  it :  they  could  swallow,  and  digest 
the  grains ;  but  they  had  no  instinct  to  make  tlicm  seek, 
no  volition  to  make  them  pick  up  the  grains.  They  savj 
nothing,  although  the  iris  remained  irritaljle ;  they  heard 

*  See  a  veiy  interesting  case  of  this  special  loss  of  memoiy  in  a  priest 
who  still  occui)ie(l  himself  reading  classic  authors  and  pcrfonning  his  of- 
ficial duties  many  months  after  an  injury  to  the  brain.  IjUs.sana  e  Le- 
.MoKiNE,  Fisiologia  dei  centri  cncefalici,  I.  201. 

vfiL.   III.  23  H  H 


530         THE  PHYSICAL  BASIS  OF  MIND. 

nothing ;  they  could  not  smell.  A  state  of  stupor  came 
on,  resembling  that  of  deep  sleep.  All  voluntary  action 
ceased.  If  they  were  thrown  into  the  air,  they  flew ;  if 
irritated,  they  moved  away;  but  if  left  to  themselves,  they 
remained  motionless,  with  the  head  under  the  wing,  as  in 
sleep.  ISTow,  inasmuch  as  these  effects  always  ensue  when 
the  Cerebrum  is  removed,  and  Tiever  when  only  the  Cere- 
bellum is  removed,  he  concludes  that  all  instincts,  voli- 
tions, and  sensations  "belong  exclusively  to  the  cerebral 
lobes." 

But  all  experimenters  do  not  agree  in  other  points 
named  by  Flourens  ;  nor  in  the  conclusions  he  has  drawn. 
On  the  contrary,  it  is  very  certain,  and  we  find  evidence 
even  in  Flourens  himself,  that  all  instincts  and  all  sensa- 
tions are  not  destroyed  by  the  removal  of  the  cerebral 
lobes. 

62.  Let  us  hear  Bouillaud  on  this  subject.*  He  re- 
peated the  experiment  of  Flourens,  removing  the  whole 
of  the  Cerebrum  from  the  Brain  of  a  fowl ;  and  he  thus 
records  his  observations :  "  This  fowl  passes  the  greater 
part  of  her  time  asleep,  but  she  awakes  at  intervals,  and 
spontaneously.  When  she  goes  to  sleep,  she  turns  her 
head  on  one  side  and  buries  it  in  the  feathers  of  the  wing  ; 
when  she  awakes,  she  shakes  herself,  flaps  her  wings,  and 
opens  her  eyes.  In  this  respect  there  is  no  difference  ob- 
servable between  the  mutilated  and  the  perfect  bird.  She 
does  not  seem  to  be  moved  at  all  by  the  noise  made  round 
about  her,  but  a  very  slight  irritation  of  the  skin  suffices 
to  awaken  her  instantaneously.  When  the  irritation 
ceases,  she  relapses  into  sleep.  When  awake,  she  is  often 
seen  to  cast  stupid  glances  here  and  there,  to  change  her 
place,  and  walk  spontaneously.  If  put  into  a  cage,  she 
tries  to  escape ;  but  she  comes  and  goes  without  any  pur- 

*  BoTTlLLAtTD,  Becherclics  Expirimentales  sur  Ics  Fondions  du  Cerveau 
en  general,  1830,  p.  5,  sq. 


THE   KEFLEX   THEORY.  531 

pose,  or  rational  design.  "VVlien  either  foot,  wing,  or  head 
is  pinched,  she  withdraws  it ;  when  she  is  laid  hold  of, 
she  struggles  to  escape,  and  screams;  but  no  sooner  is  she 
liberated  than  she  rests  motionless.  If  severely  irritated, 
she  screams  loudly;  but  it  is  not  only  to  express  pain  that 
she  uses  her  voice,  for  it  is  by  no  means  rare  to  hear  her 
cacJde  and  cluck  a  little  spontaneously ;  that  is  to  say,  when 
no  external  irritation  affects  her.  Her  stupidity  is  pro- 
found ;  she  knows  neither  objects  nor  places,  nor  persons, 
and  is  completely  divested  of  memory  in  this  respect : 
not  only  does  she  not  know  how  to  seek  or  take  food,  she 
does  not  even  know  how  to  swallow  it  when  placed  in  her 
beak  —  it  must  be  pushed  to  the  throat.  Nevertheless 
her  indocility,  her  movements,  her  agitation,  attest  that 
she  feels  the  presence  of  a  strange  body.  Inasmuch  as 
external  objects  excite  in  her  no  idea,  no  desire,  she  pays 
no  attention  to  them ;  but  she  is  not  absolutely  deprived 
of  the  power  of  attention,  for  if  much  irritated  her  atten- 
tion is  awakened.  She  knows  not  how  to  escape  an  enemy, 
nor  how  to  defend  herself  All  lier  actions,  in  a  word,  are 
blind,  without  reflexion,  without  knowledge." 

In  this  recital,  the  evidence  both  of  sensation  and  in- 
stinct is  incontestable,  to  any  unprejudiced  mind.  Bouil- 
laud,  in  commenting  on  his  observations,  remarks,  that 
assuredly  all  sensation  was  not  destroyed,  since  the  sensi- 
bilities of  touch  and  pain  were  very  manifest.  Nor  is  it 
certain,  he  says,  that  the  fowl  heard  nothing,  saw  nothing. 
It  is  true  that  she  stumbled  against  olyects,  and  knew  not 
how  to  avoid  them.  She  opened  lier  eyes  on  awaking, 
looked  about,  and  showed  a  sensibility  in  the  pupil  to 
light ;  which,  he  thinks,  is  incompatible  with  the  absence 
of  all  sensation  of  sight. 

63.  The  experiments  of  Longet*  seem  decisive  on  this 
latter  point.     Having  removed  the  whole  of  the  Cere- 

♦  Longet,  Traiie  dc  Physiologic,  II.  240. 


532  THE   PHYSICAL   BASIS   OF   MIXD. 

brum  from  a  pigeon,  lie  observed  that  whenever  he 
approached  a  light  brusquely  to  its  eyes,  there  was  con- 
traction of  the  pupil,  and  even  winking ;  but,  what  was 
still  more  remarkable,  "  when  I  gave  a  rotatory  motion  to 
the  candle,  and  at  such  a  distance  that  there  could  be  no 
sensation  of  heat,  the  pigeon  made  a  similar  movement 
with  its  head.  These  observations,  renewed  several  times 
in  the  presence  of  persons  who  were  at  my  lectures,  left 
no  doubt  of  the  persistence  of  sensibility  to  light  after 
removal  of  the  cerebral  lobes."  We  have  only  to  think  of 
the  baby  following  with  its  eyes  the  light  moved  before 
it,  to  understand  the  kind  of  impression  produced  by  the 
candle  on  the  pigeon.  Longet  also  declares  that  his  ex- 
periments prove  the  existence  of  sensations  of  sound,  after 
removal  of  the  whole  cerebrum. 

64.  Dr.  Dalton,  giving  the  results  of  numerous  experi- 
ments he  performed,  says  that  removal  of  the  Cerebrum 
plunges  the  animal  in  "  a  profound  stupor,  in  which  he  is 

almost  entirely  inattentive  to  surrounding  objects 

Occasionally  the  bird  opens  its  eyes  with  a  vacant  stare, 
stretches  his  neck,  perhaps  shakes  his  bill  once  or  twice, 
or  smoothes  down  the  feathers  upon  his  shoulders,  and 
then  relapses  into  his  former  apathetic  condition.  This 
state  of  immobility,  however,  is  not  accompanied  by  the 
loss  of  sight,  of  hearing,  or  of  ordinary  sensibilit}'".  All 
these  functions  remain,  as  vjcll  as  that  of  foluntary  motion. 
If  a  pistol  be  discharged  behind  the  back  of  the  animal, 
he  at  once  opens  his  eyes,  moves  his  head  half  round,  and 
gives  evident  signs  of  having  heard  the  report;  but  he 
immediately  becomes  quiet  again,  and  pays  no  further 
attention  to  it.  Sight  is  also  retained,  since  the  bird  will 
.sometimes  fix  its  eye  on  a  particular  object,  and  watch  it 
for  several  seconds  together."  * 

While,  therefore,  Flourens  concludes  from  his  experi- 

*  Daltox,  Human  Physiolocjij,  Philadelpliia,  1859,  p.  362. 


THE    REFLEX   THEORY.  533 

ments  that  tlie  Cerebrum  is  the  seat  of  all  sensation  and 
all  volition ;  and  Bouillaud  concludes  that  it  is  most  prob- 
abl}'-  the  seat  of  none;  Dr.  Dalton  concludes  that  the 
functions  of  the  Cerebrum  are  restricted  to  those  usually 
classed  as  intellectual.  "  The  animal,"  he  says,  "  is  still 
capable,  after  removal  of  the  hemispheres,  of  receiving 
sensations  from  external  objects.  But  these  sensations 
appear  to  make  upon  him  no  lasting  impression.  He  is 
incapable  of  connecting  with  his  perceptions  any  distinct 
succession  of  ideas.  He  hears,  for  example,  the  report 
of  a  pistol,  but  he  is  not  alarmed  by  it ;  for  the  sound, 
although  distinctly  perceived,  does  not  suggest  any  idea 
of  danger  or  injury.  The  memory  is  altogether  destroyed, 
and  the  recollection  of  sensations  is  not  retained  from  one 
moment  to  another.  The  limbs  and  muscles  are  still 
under  the  control  of  the  will ;  but  the  will  itself  is  inac- 
tive, because  apparently  it  lacks  its  usual  mental  stim- 
ulus and  direction."* 

Dr.  Dalton  reminds  us  how  disturbance  of  the  cerebral 
functions  in  human  beings  recalls  these  observations  on 
animals.  "  In  cases  of  impending  apoplexy,  or  of  soften- 
ing of  the  cerebral  substance,  among  the  earliest  and  most 
common  phenomena  is  a  loss  or  impairment  of  the  mem- 
ory. The  patient  forgets  the  names  of  particular  objects, 
or  particular  persons;  or  he  is  unable  to  calculate  num- 
l)ers  with  his  usual  facility.  His  mental  derangement  is 
often  shown  in  the  undue  estimate  which  he  forms  of 
passing  events.  He  is  no  longer  able  to  appreciate  the 
true  relation  between  different  objects  and  different  phe- 
nomena. Thus  he  will  show  an  exaggerated  degree  of 
solicitude  about  a  trivial  occurrence,  and  will  pay  no  atten- 
tion to  other  matters  of  importance.  As  the  difficulty 
increases,  he  becomes  careless  of  the  directions  and  advice 
of  his  attendants,  and  must  be  watclied  and  managed  like 

*  Dalton,  p.  362. 


534  THE   PHYSICAL  BASIS   OF   MIND. 

a  child  or  an  imbecile.  After  a  certain  period  he  no  longer 
appreciates  the  lapse  of  time,  and  even  loses  the  distinc- 
tion between  day  and  night.  Finally,  when  the  injury 
to  the  hemispheres  is  complete,  the  senses  may  still  re- 
main active  and  impressible,  while  the  patient  is  com- 
pletely deprived  of  intelligence  and  judgment."* 

65.  Having  seen  how  far  other  experimenters  are  from 
confirming  the  conclusions  of  Flourens,  let  us  glance  at 
his  record  of  observations,  and  w^e  shall  find  there  evi- 
dence that  all  sensation  and  all  volition  cannot  be  local- 
ized in  the  Cerebrum.  Speaking  of  a  fowl  whose  Cere- 
brum was  removed  the  day  before,  he  says  :  "  She  shakes 
her  head  and  feathers,  sometimes  even  she  cleans  and 
sharpens  them  with  her  beak ;  sometimes  she  changes  the 
leg  on  which  she  sleeps,  for,  like  other  birds,  she  sleeps 
habitually  resting  upon  one  leg.  In  all  these  cases  she 
seems  like  a  man  asleep,  who,  without  quite  waking, 
changes  his  place,  and  reposes  in  another,  from  the  fatigue 
occasioned  by  the  previous  posture :  he  selects  one  more 
comfortable,  stretches   himself,  yawns,  shakes  himself  a 

little,  and  falls  asleep  again On  the  third  day  the 

fowl  is  no  longer  so  calm ;  she  comes  and  goes,  but  with- 
out motive  and  without  an  aim  ;  and  if  she  encounters  an 
obstacle  on  her  path,  she  knows  not  how  to  avoid  iff 
In  his  second  work  he  remarks  of  a  Duck  operated  on  in 
the  same  way  :  "  As  I  mentioned  last  year  a  fro'pos  of 
fowls,  the  duck  walks  about  oftener,  and  for  a  longer  time 
together,  when  it  is  fasting,  than  when  it  is  fed." 

Here  he  observes  the  unmistakable  evidence  of  feelings 
of  Hunger,  Fatigue,  and  Discomfort  in  animals  which, 
according  to  him,  have  lost  all  sensation.  He  also  ob- 
serves the  operation  of  instinct  (cleaning  the  feathers), 
and  of  spontaneous  activity  (walking  about),  in  animals 
said  to  have  lost  all  instinct  and  all  volition. 

*  Dalton,  p.  363.  t  Flourens,  p.  89. 


THE   KEFLEX   THEORY.  535 

66.  Still  more  decisive  are  the  observations  recorded 
by  other  experimenters.  Leyden  removed  the  hemi- 
spheres and  the  ganglia  at  their  base  from  a  hen ;  yet  this 
hen  moved  about  and  clucked.  Meissner  noticed  that 
a  pigeon  whose  hemispheres  had  been  removed  always 
uttered  its  coo,  and  showed  restlessness  at  the  usual  feed- 
ing-time.* Voit  carefully  extirpated  the  cerebrum  from 
some  pigeons,  and  kept  them  for  many  months  in  health. 
For  the  first  few  weeks  they  exhibited  the  well-known 
stupor.  Then  they  began  to  shake  this  off,  open  their 
eyes,  walk,  and  fly  about  spontaneously.  They  gave  un- 
mistakable signs  of  seeing  and  hearing.  But  the  chief 
defect  was  in  the  inability  to  feed  themselves,  and  the 
complete  insensibility  to  danger.  They  also  manifested 
signs  of  sexual  feeling  with  lively  cooings ;  though  quite 
unable  to  gratify  their  desires,  f  Vulpian  having  removed 
the  cerebrum,  optic  thalami,  and  corpora  striata  from  a 
young  rabbit,  found  that  on  pinching  its  tail  it  cried  out 
and  struggled  to  escape ;  and  a  rat  thus  mutilated  not 
only  struggled  and  cried  when  pinched,  but  manifested 
strong  emotion.  "  II  est  tres  craintif,  tres  impressionable  ; 
il  bondit  pour  peu  qu'on  le  touche ;  le  moindre  bruit  le 
fait  tressaillir.  Un  certain  bruit  d'appel  fait  avec  les 
levres,  ou  un  soufflet  brusque  imitant  celui  qu'emettent 
les  chats  en  colere  excitent  chez  le  rat  une  vive  emotion.^ 

67.  There  are  several  well-authenticated  cases  on  rec- 
ord of  children  born  without  a  vestige  of  brain,  and  oth- 
ers with  only  a  vestige,  who  nevertheless  manifested  the 
ordinary  signs  of  sensation.  I  will  cite  but  one,  and  it 
shall  Ije  one  for  which  an  illustrious  physiologist,  Panizza, 
is  tlic  guarantee.     A  male  infant,  one  of  twins,  who  lived 

*  Leyden  in  the  Berliner  klinischc  IVochenschrift,  1867,  No.  7. 
Mei.ssseu,  Jahreshcricht  iibcr  Physiol.,  1867,  p.  410. 

t  Voit  in  the  Sitzungnherichtc  dcr  Milnchcner  Academic,  1868,  p.  105. 
Comj).  also  Goltz  in  PJlurjcr's  Archiv,  IM.  XIV.  435. 

%  VuLi'iAN,  SysUme  Ncrvcux,  542-48. 


bob  THE  niYSicAL  basis  of  mind. 

Init  eighteen  hours,  during  that  period  manifested  such 
un(}ucstionable  signs  of  Sensibility  as  the  following:  the 
pupils  contracted  under  light,  sharp  sounds  caused  iiutter- 
ings,  and  a  bitter  solution  when  placed  in  the  mouth  was 
instantly  rejected.  This  infant  had  not  a  vestige  of  cere- 
brum, cerebellum,  or  cerebral  ganglia.  The  medulla  ob- 
longata was  normal.  There  were  no  olfactory  nerves,  and 
the  optic  nerves  terminated  in  a  little  mass  of  mem- 
brane.* 

68.  The  observations  of  Lussana  and  Lemoigne  are 
both  extensive  and  precise,  and  the  conclusion  at  which 
they  arrive  is  that  the  removal  of  the  Cerebrum  is  the 
abolition  of  Intelligence  and  Instinct,  but  is  not  the  abo- 
lition of  Sensation.  Whereas  Rolando,  and  after  him 
Eenzi,  consider  that  only  the  Intelligence  is  abolished,  the 
supposed  loss  of  Instinct  being  really  nothing  more  than 
the  loss  of  the  directive  influence  which  makes  the  In- 
stinct to  be  executed. 

69.  Here  it  becomes  needful  to  understand 


THE   MECHANISM   OF   INSTINCT. 

Were  we  dealing  with  an  ordinary  mechanism,  and  the 
disturbances  produced  in  its  actions  by  the  removal  of  any 
part,  we  should  attribute  all  observed  effects  to  interfer- 
ence vjith  the  conditions  of  dependent  sequence :  we  should 
infer  that  the  actions  were  imperfectly  performed,  or 
wholly  abolished,  because  their  requisite  mechanical  con- 
ditions were  disturbed.  Let  us  be  equally  precise  in  deal- 
ing with  the  physiological  mechanism.  If  we  have  de- 
prived it  of  an  organ  in  which  certain  combinations  are 
effected,  we  must  expect  to  find  all  actions  which  were 
dependent  on  such  combinations  to  be  now  impossible ; 

*  For   other  e.xamples   see  Gintrac,   Pathologic  Interne,   1868,   VI. 
51-57. 


THE   REFLEX  THEORY.  537 

but  all  the  actions  which  are  not  directly  dependent  on 
these  combinations  may  still  be  possible.  The  actions  of 
feeding,  for  example,  are  determined  by  certain  sensations, 
when  these  are  present  in  a  particular  sequence,  but  not 
otherwise ;  the  sensation  of  sight  does  not  suffice,  because 
the  animal  must  not  only  see  the  food,  he  must  perceive  it. 
The  action  of  defence  and  flight  are  also  determined  by 
certain  sensations,  but  only  when  these  are  connected  in 
a  certain  sequence :  the  brainless  animal  will  defend  itself, 
or  move  out  of  the  Avay,  under  the  stimulus  of  unpleasant 
sensation  ;  but  wall  not  be  moved  by  o,  pi'^^ospective  injury, 
because  he  fails  to  associate  it  with  the  sight  of  the  threat- 
ening object.  In  the  same  way  a  blind  man  shrinks  at 
tlie  actual  contact  of  the  heated  poker,  but  does  not  shrink 
at  the  approach  of  that  poker  which  he  does  not  see.  We 
do  not  deny  him  the  possession  of  the  so-called  instinct 
of  Self-preservation  on  this  ground ;  why  deny  it  to  the 
brainless  animal  ?  The  brainless  fish  or  frog  swims  when 
placed  in  the  water,  because  the  sensation  from  the  mov- 
ing water  *  sets  going  the  swimming  mechanism.  To  call 
this  a  "  swimming  instinct "  may  seem  extravagant ;  yet 
it  is  as  fully  entitled  to  the  name  as  Self-defence  is,  or  the 
Alimentary  Instinct.  In  all  three  cases  there  is  a  con- 
nate mechanism  set  going  by  appropriate  feelings. 

70.  Since  all  admit  that  there  is  an  Alimentary  In- 
stinct, let  us  see  what  kind  of  mechanism  it  implies. 
There  must  be  a  state  of  feeling  called  Hunger,  which  — 
combined  with  other  feelings  —  determines  certain  mus- 
cular adjustments  in  the  search,  recognition,  capture,  and 
finally  the  swallowing  of  the  food:  —  a  very  conqjlex 
scries  of  actions,  which  lead  to  and  sustain  one  another 
until  the  desire  is  gratified.     On  the  mental  side  there 

*  If  the  water  is  jjerfectly  still  the  fish  sinks  to  the  hottorn  and  re- 
mains motionless  imtil  the  water  he  stirred.     Mere  contact  does  not  suf- 
fice ;  there  must  be  intemiittent  pulses  from  the  moving  water. 
23* 


538  THE   PHYSICAL   BASIS   OF   MIND. 

are  three  constituents,  all  indispensable  :  the  hunger  must 
be  felt,  the  food  must  be  discriminated,  the  desire  must 
be  gratified ;  on  the  physical  side  there  are  also  the 
indispensable  arrangements  of  the  motor  mechanism. 
Now  it  is  obvious  that  the  entire  mechanism  of  this  in- 
stinct cannot  be  localized  in  the  brain,  even  if  its  mental 
elements  are  localized  there ;  and  there  is  reason  to  be- 
lieve that  even  the  mental  elements  —  the  feelings  of 
hunger,  discrimination,  and  gratification  —  are  not  exclu- 
sively localized  there.  The  brainless  animal  manifests  if 
not  the  feeling  of  Hunger,  at  any  rate  that  feeling  of  dis- 
comfort which  is  the  basis  of  Hunger.  The  restlessness 
is  that  of  a  hungry  animal.  Now  we  know  that  some  of 
the  Systemic  Sensibility  is  preserved,  for  we  see  the  ani- 
mal breathing,  swallowing,  urinating,  sleeping,  preening 
its  feathers,  changing  its  attitude,  resting  on  one  leg  after 
the  fatigue  of  the  other,  etc.  AVe  may  therefore  infer  that 
other  systemic  sensations,  such  as  Hunger  and  Thirst, 
arise  under  the  usual  conditions. 

71.  We  have  noted  an  indication  of  Hunger ;  but  on 
further  observation  we  discover  that  although  the  food  is 
eaten,  if  brought  within  reach  of  that  portion  of  the  feed- 
ing mechanism  which  is  still  intact,  yet  the  second  step 
—  the  feeling  of  recognition  —  is  wanting.  The  animal 
fails  to  perceive  the  food  brought  under  his  eyes,  or  even 
placed  in  his  mouth ;  unless  the  back  part  of  the  mouth 
be  touched,  no  swallowing  takes  place.  Hence  the  animal 
can  no  longer  feed  himself,  and  is  therefore  said  to  have 
lost  his  instinct.  But  although  the  mechanism  of  the 
instinct  has  been  disturbed,  its  action  is  not  wholly  abol- 
ished. The  brain  is  necessary  for  that  combination  of 
adjustments  which  normally  accompany  the  perception 
of  food  through  sight  and  scent;  and  its  absence  of  course 
frustrates  such  combination ;  but  we  shall  presently  see 
that  although  certain  sensible  marks  by  which  a  percep- 


THE  REFLEX  THEORY.  539 

tion  is  guided  are  absent,  others  may  still  be  present,  and 
suffice. 

72.  Before  adducing  examples  let  me  say  that  we  can- 
not legitimately  attribute  the  abeyance  of  an  instinct 
solely  to  the  absence  of  the  brain,  1°,  because  we  ob- 
serve a  similar  abeyance  of  the  instinct  and  frustration 
of  perception,  even  when  the  brain  is  present,  and  the 
animal  is  in  its  normal  state.  2°.  On  the  other  hand, 
some  instincts  are  unmistakably  manifested,  and  some 
perceptions  excited,  after  the  brain  has  been  removed. 
In  fact,  all  that  is  needful  is  that  some  of  the  mental 
elements  of  such  perception  and  such  instinct  be  pre- 
served; and  this  is  the  case  so  long  as  the  leading 
element  is  present. 

73.  On  the  first  point  consider  this  unequivocal  ex-, 
ample.  A  healthy,  hungry  frog  may  be  placed  in  a  ves- 
sel in  which  lie  a  quantity  of  dead  flies.  He  sees  these 
flies,  but  sight  is  not  enough ;  to  him  they  are  only  so 
many  black  spots,  in  which  he  does  not  recognize  his 
food,  because  the  flies  do  not  move,  and  the  leading 
dement  in  his  perception  of  food  is  not  a  colored  form, 
but  a  moving  form.  Hence  this  frog,  in  spite  of  brain  and 
an  intact  organism,  will  starve  amidst  appropriate  food. 
Whereas  the  frog  that  will  not  snap  at  motionless  flies 
snaps  at  any  other  small  moving  object,  though  it  be  not 
his  food.  Goltz  ol)served  one  incessantly  snapping  at  the 
moving  tentacles  of  a  slug  which  was  in  the  vessel — as 
if  that  were  possible  food !  Not  only  the  stupid  frog,  but 
the  more  intelligent  carnivora  will  starve  in  the  presence 
of  appropriate  food  which  is  unrecognized,  because  the 
leading  element  in  tlie  recognition  is  absent.  The  cat 
will  not  eat  a  dead  mouse,  unless  slie  has  killed  it  herself. 
Predatory  animals  must  capture  their  food  —  unless  the 
scent  of  blood  excites  their  alimentary  instinct.  So  inti- 
mately is  this  sensation  of  a  moving  object  connected 


540  THE   PHYSICAL  BASIS   OF   MIXD. 

with  the  predatory  impulse,  that  the  cat  which  is  unex- 
cited  by  the  dead  mouse  cannot  resist  springing  on  a 
moving  ball.  We  need  not  suppose  the  cat  to  mistake 
this  ball  for  food ;  but  we  must  suppose  that,  accustomed 
to  pounce  upon  moving  food,  it  is  unable  to  resist  the 
impulse  of  this  leading  sensation. 

74.  The  2y^'cscncc  of  the  brain  not  sufficing,  in  the  ab- 
sence of  the  leading  sensation,  we  shall  now  see  that  the 
absence  of  tlie  brain  will  not  prevent  the  execution  of  the 
instinctive  action,  if  the  leading  sensation  be  present. 
The  brainless  bird  sees  a  heap  of  grain,  or  a  pan  of 
water,  but  no  more  recognizes  them  by  sight  alone  than 
the  frog  recognizes  the  dead  flies ;  yet  if  the  bird's  feet  be 
placed  in  the  water,  this  sensation  will  suffice  to  make 
him  drink ;  if  placed  amid  the  grain,  this  sensation  will 
(sometimes)  suffice  to  make  him  feed.  Lussana  and  Le- 
moigne  state  that  their  brainless  pigeons  ate  and  drank 
with  avidity  when  their  feet  were  placed  in  grain  and 
water.*  M.  Krishaber  removed  the  hemispheres  from  a 
pigeon,  and  observed  that  when  his  beak  was  thrust  into 
a  heap  of  hempseed  the  head  was  quickly  withdrawn, 
whereas  when  the  beak  was  plunged  into  water  the  bird 
drank  eagerly.  Every  day  he  was  forced  to  feed  the  bird 
by  pouring  the  seed  into  its  throat,  but  every  day  it 
drank  when  the  beak  was  thrust  into  the  pan  of  water.-f- 
Briicke  noticed  that  his  brainless  hen,  which  made  no 
attempt  to  peck  at  the  grain  under  her  very  eyes,  began 
pecking  if  the  grain  were  thrown  on  the  ground  with 
force,  so  as  to  produce  a  rattling  sound.  The  sensation 
of  hearing  was  here  more  perfect  than  that  of  vision,  and 
sufficed  to  awaken  the  state  of  feeling  necessary  to  initiate 
the  pecking  movement.;): 

*  Lussana  e  Lf.moigne,  Oj).  cit.,  I.  15. 
+  Archives  de  Physiologic,  1869,  p.  539. 
J  Bkucke,  Physiologic,  II.  p.   63.     WTiile  these  sheets  are  passing 


THE   KEFLEX   THEOEY,  541 

75.  Somewliat  analogous  phenomena  are  observed  in 
Aphasia.  The  patient  can  see  printed  or  written  letters, 
and  even  copy  them ;  but  he  cannot  read,  i.  e.  interpret, 
these  symbols;  as  the  birds  see  the  grain,  but  cannot  con- 
nect this  sensation  with  others.  These  letters  and  words, 
which  the  patient  cannot  interpret  when  seen,  he  can  in- 
terpret when  heard;  he  can  not  only  understand  them 
when  spoken,  but  write  them  if  they  are  dictated  to  him. 
The  birds  recognize  the  grain  and  water  (or  act  as  if  they 
did)  wlien  other  sensations  than  those  of  sight  are  ex- 
cited. Sound  is  the  leading  element  in  Language,  both 
spoken  and  written.  "We  hear  the  M^ords  even  when  we 
see  them,  but  we  do  not  see  them  when  we  hear  them. 
The  visible  symbols  are  accessory  and  subordinate.  But 
to  the  born  deaf  the  visible  symbols  dominate.  How  one 
sensation  will  determine  a  particular  group  of  movements 
which  cannot  be  effected  by  any  other  stimulus  is  abun- 
dantly illustrated  in  disease  no  less  than  in  experiment. 
Here  is  a  very  luminous  example:  Gratiolet  had  a  patient 
for  six  months  under  his  eye  incapable  of  articulating  a 
single  word,  owing  to  the  incoherence  of  her  incessant  ut- 

tlirough  the  press,  GoLTZ  has  published  his  second  series  of  experiments 
on  the  brain.  Tlie  following  detail  is  a  good  illustration  of  what  is  said 
in  the  text:  A  dog  deprived  of  a  portion  of  both  hemisjiheres  displayed 
a  marked  imperfection  in  the  execution  of  ordinary  instincts.  Although 
sight  was  impaired  he  could  see,  and  recognize  men  and  certain  objects: 
the  sight  of  a  wliip  made  him  cower,  but  the  sight  of  meat  did  not  suf- 
fice to  set  the  feeding  mechanism  in  action.  When  meat  was  suspended 
above  his  head,  the  scent  caused  him  to  sniff  about  in  search,  but  he 
failed  to  find  it,  and  even  when  he  was  so  placed  that  he  could  see  the 
susjjcnded  meat,  the  unusual  impression  failed  to  guide  him.  If  the 
meat  were  held  towards  him,  or  placed  before  him  in  a  dish,  he  took  it 
at  once  — this  being  the  customary  stimulation.  So  also,  if  the  hand 
were  held  up,  in  the  usual  way  when  dogs  are  made  to  leap  for  food,  this 
dog  sprang  vigorously  up  and  caught  the  food ;  but  he  would  spring  up 
in  the  .same  way  when  the  hand  was  held  empty,  and  continue  fruitlessly 
springing,  whereas  an  uninjured  dog  ceases  to  sj)nng  wiien  he  sees  the 
hand  is  empty.  — Pflikjcrs  Archiv,  lid.  XIV.  p.  419. 


542  THE   PHYSICAL   BASIS   OF   MIND. 

terance  —  she  babbled  sounds,  but  could  not  group  the 
syllables  into  a  recognizable  word.  Yet  she  could  sing 
the  words  of  any  song  she  knew,  the  musical  sensations 
being  sufficient  to  guide  her  vocal  organs.  "Ainsi  la 
meinoire,  infidele  dans  le  cas  oii  les  mots  etaient  des 
idees,  devenait  claire  et  precise  quand  les  mots  etaient 
des  chansons."  * 

76.  These  illustrations  plainly  tell  how  the  brainless 
animal  may  starve  amid  his  food,  failing  to  perceive  it 
because  tlie  leading  sensation  is  not  excited ;  and  how  the 
same  animal  may  manifest  his  feeding  instinct  if  the 
mechanism  be  set  going  by  a  leading  sensation.  We  are 
told,  indeed,  that  in  the  absence  of  the  brain  the  actions 
are  mechanical  reflexes  from  impressions,  and  not  com- 
parable with  the  complex  processes  determined  by  per- 
ception. I  think,  however,  that  tlie  only  difference  is  in 
degree  of  complexity :  a  combination  of  touch,  tempera- 
ture, and  muscular  movement  will  be  simpler  than  one 
which  also  combines  sight,  smell,  and  the  revived  images 
of  associated  sensations.  The  sight  of  a  sheep  affects  the 
instinctive  mechanism  of  a  wolf  only  when  combined 
with  the  leading  element  of  smell.  Place  a  stuffed  sheep 
in  a  field,  and  no  wolf  will  approach  and  spring  on  it, 
whereas  the  blind  wolf  will  find  and  capture  the  real 
sheep ;  and  I  believe  that  were  it  practicable  to  remove 
the  brain  without  injury  to  the  organ  of  scent  and  the 
powers  of  locomotion,  the  wolf  would  track  and  capture 
the  living  sheep. 

77.  The  outcome  of  this  discussion  is  that  the  mechan- 
ism of  each  instinct  is  the  adjustment  of  the  organs  which 
effect  the  instinctive  action ;  and  this  adjustment  is  not 
simply  a  cerebral  process,  but  a  complex  of  many  sensorial 
processes ;  consequently  the  instinct  cannot  be  exclusively 
localized  in  the  brain,  altliough  the  cerebral  process  may 

*  Gratiolet,  Anat.  Comparee  die  SysUme  Nerveux,  1857,  p-  459. 


THE   KEFLEX  THEOKY.  543 

be  a  very  important  element  in  the  adjustment.  This  is 
true  even  on  the  supposition  that  in  speaking  of  Instinct 
we  refer  only  to  the  state  of  feeling  which  originates  the 
action  —  separating  the  psychological  from  the  physiologi- 
cal aspect  of  the  phenomenon.  \^or  the  brain  minus  the 
organism  is  obviously  incapable  of  feelings ;  whereas  the 
organism  minus  the  brain  is  obviously  capable  of  sensi- 
bilities adequate  to  determine  the  actions.  Thus  the  feel- 
ing of  hunger  which  prompts  the  alimentary  actions  does 
not  arise  if  tlie  animal  is  satiated,  nor  does  the  sexual 
feeling  which  prompts  generative  actions  arise  when  the 
animal  is  castrated ;  but  each  arises  when  the  organism  is 
in  a  particular  state.  In  vain  will  food  be  placed  before 
the  satiated  animal,  or  a  female  before  the  castrated  male; 
food  and  female  are  seen  and  recognized,  but  no  desires 
are  excited,  in  spite  of  the  brain  and  its  supposed  in- 
stincts. On  the  contrary,  when  the  brain  is  removed,  the 
need  of  tlie  organism  for  food  is  felt,  and  this  need  deter- 
mines restless  movements,  which  are  directed  by  certain 
other  sensations,  and  the  instinctive  action  of  feeding  is 
finally  effected ;  although,  of  course,  the  removal  of  the 
brain  has  so  disturbed  the  normal  mechanism  of  the  in- 
stinct that  the  action  is  imperfect.  Renzi  says  that  an 
animal  deprived  of  its  brain  has  lost  the  intelligence 
which  enables  it  to  seek  and  seize  its  food,  but  not  the 
instinct,  since  it  still  has  the  desire  for  food.  The  fol- 
lowing experiment  may  illustrate  this.  Eenzi  wounded 
superficially  one  optic  thalamus  of  a  frog  without  in- 
juring the  external  margin,  or  optic  tract.  Tlie  frog 
showed  no  appreciable  loss  of  sight,  but  hopped  timidly 
away  whenever  approached.  Then  botli  thalami  were 
divided  transversely,  the  optic  tract  still  being  spared. 
This  frog  remained  motionless  under  every  threat.  It 
manifested  no  alarm,  and  even  when  directly  irritated, 
only  crawled  or  hopped  away  like  a  brainless  frog.    Sight 


544  THE   PHYSICAL   BASIS   OF   JIIND. 

still  SO  far  remained  that  obstacles  were  avoided*  Now 
since  this  animal's  brain  was  intact,  and  its  organs  of 
movement  were  capable  of  responding  to  stimulation, 
how  are  we  to  explain  the  loss  of  its  instinct  of  self- 
preservation  ?  The  i'rog  perceived  no  danger  in  a  threat- 
ening approach,  yet  perceived  an  obstacle  and  avoided  it, 
getting  under  it  if  there  were  room  enough,  crawling  be- 
side it  if  that  was  the  easier  escape.  Why  did  one  vision 
prompt  the  movements  of  escape,  and  another  fail  ?  AVas 
it  not  that  in  the  one  case  the  normal  pathway  was  still 
open,  in  the  other  closed?  We  know  that  one  injury 
will  destroy  the  perception  of  color  without  destroying 
that  of  light  and  shadow ;  so  one  injury  may  destroy  the 
combination  of  neural  processes  necessary  for  the  percep- 
tion of  a  danger,  without  destroying  those  necessary  for 
the  perception  of  a  hindrance.  If  all  actions  depend 
on  their  mechanical  conditions,  they  must  be  disturbed 
according  to  the  disturbance  of  the  conditions.  Nothna- 
gel  found  that  after  removing  the  nucleus  Icntiformis  on 
both  sides  of  a  rabbit,  leaving  all  the  rest  of  the  encepha- 
lon  intact,  the  rabbit  hopped  when  its  tail  was  pinched ; 
yet  although  starting  at  the  sound  when  hands  were 
loudly  clapped,  did  not  hop  as  a  normal  rabbit  does ;  nor 
although  closing  his  eyes  when  a  light  was  brought  near 
them,  did  he  ever  move  aside.  No  feeling  of  danger  was 
excited  by  sound  or  sight.  In  striking  contrast  are  the 
phenomena  manifested  by  a  rabbit  whose  corpora  striata 
have  been  removed :  it  is  with  difficulty  made  to  hop  by 
pinching  its  skin,  whereas  noises  and  sights  cause  it  to 
make  terrified  bounds.-f* 

*  Ltjssana  e  Lemoigne,  Op.  cit.,  I.  363. 

+  Virclioiv' s  Archiv,  Bd.  LX.  pp.  130-33.  Yet  there  are  many  physi- 
ologists who  persist  in  placing  the  motorium  commune  in  the  corpora 
striata  !  And  they  place  the  scnsorium  commune  in  the  optic  thalami, 
although,  not  to  mention  the  ambiguous  evidence  of  Pathology,  the  ex- 
periments of  NoTHNAGEL  and  VEYSSifeRE  show  that  destniction  of  the 


THE   REFLEX  THEOEY.  545 

78.  No  sooner  do  we  analyze  the  conditions  of  an  in- 
stinct than  we  see  the  error  of  recrardins  instincts  as  local- 
ized  in  the  brain.  The  cerebral  process  is  only  one  factor 
in  the  product  —  an  important  factor,  no  doubt,  since  the 
cerebrum  is  the  supreme  centre  of  incitation  and  regu- 
lation ;  but  its  absence  does  not  wholly  carry  away  the 
activity  of  the  mechanism,  sentient  and  motor,  on  which 
the  instincts  depend,  it  only  carries  away  one  source  of 
stimulation  and  regulation. 

79.  An  instinct  depends  on  a  connate  mechanism.  Let 
us  glance  for  a  moment  at  a  parallel  case  of  an  ordinary 
reflex  action,  also  dependent  on  a  connate  mechanism,  say 
that  of  sneezing.  When  the  inner  surface  of  the  nose  is 
stimulated  by  snuff,  or  other  irritant,  the  nasal  branch  of 
the  trigeminus  is  excited,  and  the  effects  are  first  a  deep 
inspiration,  then  a  closure  of  the  respiratory  orifices  by 
the  tongue,  which  in  turn  excites  a  spasmodic  expiration. 
But  the  same  effects  are  producible  from  quite  different 
stimulations  —  namely,  that  of  the  ciliary  nerves  on  sud- 
den exposure  to  a  glare  of  sunshine  —  or  of  the  skin 
nerves  on  a  sudden  draught  of  cold  air.  Briicke  re- 
marks that  there  is  perhaps  no  spot  on  the  surface  of 
the  body  from  which  this  reflex  may  not  be  excited  in 
very  sensitive  people.  He  knew  a  gentleman  who  always 
sneezed  when  in  winter  he  laid  hold  of  a  cold  door-bell ; 
and  the  fit  of  sneezing  was  only  arrested  by  giving  him  a 
crust  of  bread  or  something  hard  to  gnaw.  Now  just  as 
the  connate  mechanism  of  sneezing  may  be  set  in  action 
l)y  a  variety  of  stimulations,  so  may  the  connate  mechan- 
ism of  an  instinct. 

tlialami  does  not  destroy  sensation.  See  VEYS.sifeRE,  Hechcrchcs  sur 
VhemianestJiesie  de  cause  ccribralc,  1874,  pp.  83,  84.  I  may  observe,  in 
passin;^,  tliat  the  notion  of  tlie  coiyora  striata  being  tlie  necessary  cliannel 
tor  volitional  impulses,  and  the  optic  thalami  for  rede.v  aetions,  is  utterly 
dispioved  by  the  experimental  evidence  recorded  in  the  text,  as  well  as 
in  §  66. 

1 1 


546  THE   PHYSICAL  BASIS   OF  MIND. 


ACQUISITION. 

80.  Not  only  may  Discrimination  and  Instinct  be  mani- 
fested in  the  absence  of  the  brain,  but  even  the  acquisi- 
tion of  new  modes  of  reaction,  such  as  are  classed  under 
Learning  through  Experience.  The  objection  is  some- 
times urged  that  animals  without  their  brains  only  mani- 
fest single  reactions  on  stimulation  —  the  pinched  foot 
is  withdrawn,  and  then  remains  motionless  until  again 
pinched.  But  although  the  stimulation  does  not  excite 
a  consecutive  series  of  movements,  because  there  is  no 
cerebrum  to  react  in  successive  stimulation,  this  does  not 
prove  the  absence  of  sensation  in  the  one  movement 
which  is  excited.  If  my  hand  be  lying  on  the  table,  and 
something  irritates  it,  my  hand  is  withdrawn,  and  then 
remains  as  motionless  as  the  limb  of  the  brainless  animal, 
until  some  fresh  stimulation,  external  or  internal,  moves 
it.  Although  removal  of  the  brain  causes  a  manifest  re- 
duction in  the  variety  and  succession  of  the  movements, 
all  experimenters  are  agreed  that  animals  acquire  a  cer- 
tain dexterity  in  executing  actions  which  they  had  pre- 
viously failed  to  carry  out  after  removal  of  their  brains. 
"There  is,"  says  Freusberg,  "a  decided  improvement  ac- 
quired in  the  reactions  of  the  motor  centres  after  division 
of  the  spinal  cord,  not  indeed  in  vigor,  but  in  delicacy. 
Eemoved  from  the  regulating  influence  of  the  brain,  the 
legs  acquired  through  practice  a  power  of  self-regulation." 
Nor  is  this  wonderful :  pathways  are  made  easy  by  repeti- 
tion of  impulses,  and  new  adaptations  form  new  adjust- 
ments. It  is  thus  all  learning  is  effected  —  intelligent, 
and  automatic.  Nor  is  there  any  force  in  the  objection 
that  the  power  thus  acquired  speedily  disappears,  so  that 
if  the  stimulations  are  effected  at  long  intervals  the  reac- 
tions do  not  manifest  their  acquired  dexterity.  The  spinal 
centres  forget,  as  the  cerebral  centres  forget;  but  they  also 


THE   REFLEX  THEORY.  547 

remember,  i.  e.  they  learn.  Because  an  animal  shows  to- 
day none  of  the  aptitude  it  acquired  three  days  ago,  we 
are  not  to  deny  that  it  had  once  acquired  the  aptitude 
it  lias  now  lost.  Attempt  to  teach  a  child  to  read  by 
giving  it  spelling  lessons  of  two  or  three  minutes  at  inter- 
vals of  two  or  three  months,  and  little  will  the  acqui- 
sition be ! 

81.  Hitherto  we  have  been  considering  phenomena 
manifested  in  the  absence  of  the  cerebral  hemispheres, 
because  it  is  in  these  that  the  majority  of  writers  place 
the  sensorium.  There  are,  indeed,  many  authoritative 
writers  who  regard  the  ganglionic  masses  at  the  base  of 
the  cerebrum,  and  even  those  of  the  medulla  oblongata,  as 
participating  in  this  sensorial  property,  which  they  refuse 
to  the  lower  ganglia  in  the  spinal  cord.  I  cannot  follow 
their  logic.  The  cerebrum  is  by  its  position  as  a  centre 
of  centres,  and  its  detachment  from  all  direct  innervation 
of  organs,  so  different  from  the  rest  of  the  neural  axis, 
that  we  can  understand  how  it  should  be  assigned  a 
special  function ;  although  being  of  the  same  tissue  as 
the  other  ganglionic  masses,  it  must  have  the  same  prop- 
erty. And  Avhat  that  special  function  is  I  shall  hereafter 
endeavor  to  set  forth.  But  that  the  upper  region  of  the 
spinal  axis  should  differ  so  profoundly  from  the  lower 
region  as  to  be  the  seat  of  psychical  processes,  while  the 
lower  region  is  simply  the  seat  of  mechanical  processes, 
is  what  I  cannot  understand,  so  long  as  the  anatomical 
structure  and  physiological  properties  of  the  two  regions 
are  seen  to  be  identical.  The  various  centres  innervate 
A'arious  organs,  and  have  consequently  various  functions. 
As  each  centre  is  removed,  we  observe  a  corresponding 
loss  of  function  —  the  organism  is  truncated,  but  con- 
tinues to  manifest  such  functions  as  have  still  their 
mechanisms  intact.     Let  us  suppose  the  brain  or  upper 


548  THE   PHYSICAL   BASIS    OF   MIND. 

regions  of  the  cord  detached  from  the  lower  regions  by  a 
section  of  the  cord ;  the  animal  will  still  live,  and  per- 
form almost  all  its  functions  in  the  normal  way,  but  there 
will  be  little  or  no  consensus  between  the  lower  and  the 
upper  regions.  Granting  Sensibility  to  both,  we  must 
still  see  that  the  sensation  excited  in  one  will  not  be  felt 
in  the  other.  And  this  is  the  ground  on  which  physiolo- 
gists deny  that  the  lower  regions  have  Sensibility.  With- 
out pausing  here  to  examine  this  point,  which  will  occupy 
us  in  the  next  chapter,  I  assume  that  the  positive  evi- 
dence of  Sensibility  suffices  to  discredit  that  argument ; 
and  in  furtherance  of  that  assumption  will  cite  an  ex- 
ample of  sensation  and  volition  manifested  by  the  lower 
portion  of  the  cord  when  separated  from  the  brain  and 
upper  portion. 

82.  The  function  of  Urination  is  one  which  notori- 
ously belongs  to  the  voluntary  class,  in  so  far  as  it  is 
initiated  or  arrested  by  a  voluntary  impulse,  and  it  is  one 
which,  according  to  the  classic  teaching,  has  its  centre  in 
the  brain.  The  grounds  on  which  this  cerebral  centre  is 
assigned  are  very  similar  to  those  on  which  other  func- 
tions are  assigned  to  cerebral  centres,  namely,  observation 
of  the  suppression  of  the  function  when  the  pathway 
between  certain  organs  and  the  brain  is  interrupted. 
But  the  careful  experiments  of  Goltz  *  have  demonstrated 
that  the  "  centre "  of  Urination  is  not  in  the  brain,  but 
in  the  lower  region  of  the  cord.  When  the  cord  is  com- 
pletely divided.  Urination  is  performed  in  the  normal 
way  —  not  passively,  not  irregularly,  but  with  all  the 
characters  of  the  active  regular  function.  And,  what  is 
also  noticeable,  this  function  is  so  intimately  dependent 
on  Sensibility  that  it  will  be  arrested  —  like  any  other 
function  —  by  a  sensation  excited  from  the  periphery  — 
to   be  resumed  when   the   irritation   ceases.     Now  this 

*  Pfliigcrs  Archil;  Bde.  VIII.  and  IX. 


THE   KEFLEX  THEORY.  549 

arrest  from  a  stimulation  of  sensory  nerves  takes  place 
when  the  brain  is  cut  off  from  tlie  spinal  centre,  just  as 
when  the  brain  is  in  connection  with  it. 

The  same  is  true  of  Defecation,  and  the  still  more 
complex  functions  of  Generation  and  Parturition.  I  can 
only  refer  the  reader  to  the  very  remarkable  case  of 
Goltz's  bitch  with  the  spinal  cord  divided  in  the  lumbar 
region,  if  evidence  be  wanted  for  the  performance  of 
complex  functions  so  long  as  the  spinal  centres  were  intact. 
It  is  true  that  Goltz  considers  these  functions  to  have 
been  independent  of  sensation;  but  that  is  because  he 
has  not  entirely  emancipated  himself  from  the  traditional 
views ;  for  my  purpose  it  is  enough  that  he  admits  the 
functions  to  be  dependent  on  sensorial  processes. 

83.  To  sum  up  the  evidence,  we  may  say  that  observa- 
tion discloses  a  surprising  resemblance  in  the  manifesta- 
tions of  the  cord  and  brain.  In  both  there  are  reflex  pro- 
cesses, and  processes  of  arrest ;  in  both  there  are  actions 
referable  to  conscious  and  unconscious  processes  ;  in  both 
depression  and  exaltation  are  produced  by  the  same  drugs ; 
in  both  there  are  manifestations  interpretable,  as  those 
of  Discrimination,  Logic,  Instinct,  Volition,  Acquisition, 
Memor}^ ;  in  both  there  is  manifestation  of  Sensibility  — 
how  then  can  we  deny  Sensation  to  the  one  if  we  accord 
^  it  to  the  other  ? 


550  THE   PHYSICAL  BASIS   OF  MIND. 


CHAPTER  IV. 

NEGATIVE  INDUCTIONS. 

84.  I  FANCY  some  reader  exclaiming  -:  "  All  your  reason- 
ing, and  all  your  marshalled  facts,  are  swept  away  by 
the  irresistible  eyidence  of  human  patients  with  injured 
spinal  cords,  whose  legs  haye  manifested  reflex  actions, 
and  who  nevertheless  declared  they  had  no  sensation 
whatever  in  them.  We  can  never  be  sure  of  what  passes 
in  an  animal ;  but  man  can  tell  us  whether  he  feels  an 
impression,  or  does  not  feel  it ;  and  since  he  tells  us  that 
he  does  not  feel  it,  cannot,  however  he  may  try,  we 
conclude  that  reflex  action  may  take  place  without 
sensation." 

As  this  is  the  one  solitary  fact  which  is  held  to  nega- 
tive the  mass  of  evidence,  anatomical  and  physiological, 
in  favor  of  the  Sensibility  of  the  spinal  cord,  it  is  neces- 
sary that  we  should  candidly  examine  it.  No  reader  will 
suppose  that  during  the  twenty  years  in  which  I  have 
advocated  the  doctrine  expounded  in  this  volume,  I  have 
not  been  fully  alive  to  the  one  fact  which  prevented  the 
general  acceptance  of  the  doctrine.  From  the  first  it  has 
seemed  to  me  that  the  fact  has  been  misinterpreted. 

85.  Certain  injuries  to  the  spinal  cord  destroy  the 
connection  of  the  parts  below  tlie  injury  with  the  parts 
above  it ;  consequently  no  impression  made  on  the  limbs 
below  the  injured  spot  is  transmitted  to  the  brain,  nor 
can  any  cerebral  incitation  reach  those  limbs.  The 
patient  has  lost  all  consciousness  of  these  limbs,  and  all 


THE   REFLEX   THEORY.  551 

control  over  them.  Hunter's  patient  on  being  asked  if  he 
lelt  any  pain  when  the  prick  caused  his  leg  to  kick, 
answered,  "  No  :  but  you  see  my  leg  does."  This  answer 
has  been  regarded  as  a  drollery ;  1  think  it  expressed  a 
physiological  truth.  For  on  the  assumption  that  the 
whole  of  the  cerebro-spinal  axis  had  one  uniform  prop- 
erty, corresponding  with  its  uniform  structure,  and  vari- 
ous functions,  corresponding  with  the  variety  of  organs 
it  innervates,  a  division  of  this  axis  would  necessarily 
create  two  independent  seats  of  Sensibility,  and  inter- 
rupt the  consensus  of  their  functions.  In  such  a  case  it 
would  be  absurd  to  expect  that,  the  cerebral  segment 
could  be  affected  by,  or  co-operate  with,  what  affected  the 
spinal  segment. 

Now,  when  a  man  has  a  diseased  spinal  cord,  the  seat 
of  injury  causes,  for  the  time  at  least,  a  division  of  the 
whole  group  of  centres  into  two  independent  groups. 
For  all  purposes  of  sensation  and  volition  it  is  the  same 
as  if  he  were  cut  in  half ;  his  nervous  mechanism  is  cut 
in  half.  How  then  can  any  cerebral  control  be  obeyed 
by  his  legs ;  how  can  any  impression  on  his  legs  be  felt 
by  his  cerebrum  ?  As  well  might  we  expect  the  man 
whose  arm  has  been  amputated,  to  feel  the  incisions  of 
the  scalpel,  when  that  limb  is  conveyed  to  the  dissecting- 
table,  as  to  feel  by  his  brain  impressions  made  upon  parts 
wholly  divorced  from  organic  connection  with  the  brain. 

86.  But,  it  may  be  objected,  this  is  the  very  point 
urged.  The  man  himself  does  not  feel  the  impressions 
on  his  legs  when  his  spine  has  been  injured;  he  is  as 
insensible  to  them  as  to  the  dissection  of  his  amputated 
arm.  Very  true.  He,  does  not  feel  it.  But  if  the 
amputated  arm  were  to  strike  the  anatomist  who  began 
its  dissection,  if  its  fingers  were  to  grasp  the  scalpel,  and 
push  it  away,  or  with  the  thumb  to  rub  off  the  acid 
irritating  one  of  the  fingers,  I  do  not  see  how  we  could 


552  THE   PHYSICAL   BASIS    OF   MIND. 

refuse  to  admit  that  the  arm  felt  although  the  man  ditl 
not.  And  this  is  the  case  \vith  the  extremities  of  a  man 
whose  spine  is  injured.  They  manifest  every  indication 
of  sensibility.  In  the  frog  and  pigeon  the  legs  manifest 
the  unmistakable  control  which  we  ascribe  to  volition. 
It  is  true  that  the  man  himself,  when  interrogated, 
declares  that  he  feels  nothing  ;  the  cerebral  segment  has 
attached  to  it  organs  of  speech  and  expressive  features, 
by  which  its  sensations  can  be  communicated  to  others ; 
whereas  the  spinal  segment  has  no  such  means  of  com- 
municating its  sensations ;  but  those  which  it  has,  it 
cm^ploys.  You  can  ask  the  cerebral  segment  a  question, 
which  can  be  heard,  understood,  and  answered ;  this  is 
not  the  case  with  the  spinal  segment :  yet  if  you  test  its 
sensibility,  the  result  is  unequivocal.  You  cannot  ask 
an  animal  whether  it  feels,  but  you  can  test  its  sensi- 
bility, and  that  test  suffices. 

87.  The  question  we  have  to  decide,  therefore,  is  not 
whether  a  patient,  with  an  injured  spine,  can  feel  im- 
pressions on,  or  convey  voluntary  impulses  to,  limbs  be- 
low the  seat  of  injury  —  for  as  respects  the  nervous 
mechanism  these  limbs  are  separated  from  him,  no  less 
than  if  actual  amputation  had  taken  place  —  the  ques- 
tion is,  whether  tliese  separated  limbs  have  any  sensibility  ? 
And  the  answer  seems  to  me  unequivocally  affirmative. 
I  assert,  therefore,  that  if  there  is  ample  evidence  to  show 
that  the  spinal  centres  have  sensibility,  when  separated 
from  the  cerebral  centres,  such  evidence  can  in  no  re- 
spect be  weakened  by  the  fact  that  a  man  with  an  in- 
jured spine  is  unconscious  of  impressions  made  below 
the  seat  of  injury ;  since  such  a  fact  necessarily  follows 
from  the  establishment  of  two  centres :  the  parts  above 
are  then  not  sensitive  to  impressions  on  the  parts  below ; 
nor  are  the  parts  below  sensitive  to  impressions  on  the 
parts  above ;  but  each  segment  is  sensitive  to  its  own 
affections. 


i 


THE    REFLEX    THEORY.  553 

88.  Every  one  knows  that  there  are  animals,  low  down 
in  the  scale,  which  may  be  cut  in  two,  each  half  continu- 
ing to  live,  and  each  capable  of  reproducing  its  lost 
segments.  Would  any  one,  seeing  these  separated  halves 
move  and  manifest  ordinary  signs  of  sensibility,  venture 
to  say  that  the  one  half  was  a  living,  the  other  an  insen- 
tient, mechanism  ?  And  since  the  one  half  had  eyes, 
mouth,  tentacles,  etc.,  while  the  other  half  had  none  of 
these,  would  the  observer  be  surprised  that  the  functions 
of  the  one  differed  from  those  of  the  other  in  these  re- 
spects ?  Why,  then,  should  he  not  conclude  the  same  of 
the  two  halves  of  the  human  mechanism,  when  disease 
had  divided  them  ? 

89.  The  man,  you  urge,  does  not  feel  the  prick  on  his 
leg.  This  is  true,  because  "  the  man "  here  designates 
the  seeing,  hearing,  tasting,  smelling,  talking,  thinking 
group  of  organs  —  to  the  exclusion  of  the  limb  or  limbs 
which  are  no  longer  in  sensitive  connection  with  this 
group.  When  a  leg  is  amputated  "  the  man  "  remains  — 
a  truncated  man,  indeed,  yet  still  one  having  all  the  dis- 
tinguishing human  characters.  Yet  obviously  in  strict 
language  we  can  no  longer  say  that  the  man  is  the  same  as 
he  was.  "Man"  or  "animal"  means  the  complex  whole; 
and  eacli  anatomically  separable  part  forms  one  constitu- 
ent of  that  whole.  The  medulla  oblongata  and  spinal 
cord  innervate  certain  parts ;  the  mesencephalon  inner- 
vates others ;  the  cerebrum  rises  above  the  whole.  If 
after  removing  one  limb,  then  another,  we  continued 
truncating  the  organism  till  we  left  only  the  head,  should 
we  call  that  the  man  ?  Clearly  not.  Should  we  even 
suppose  that  the  intact  brain  —  the  supposed  seat  of  sen- 
sation and  volition  —  still  felt,  and  willed  ?  Clearly  not. 
There  is  absolutely  no  evidence,  however  faint,  of  the 
isolated  head  manifesting  any  sensational  and  volitional 
phenomena ;  whereas  there  is  ample  evidence  of  the  trun- 

vou  III.  24 


554  THE  PHYSICAL  BASIS   OF  MIND. 

cated  spinal  cord  manifesting  some  of  these  phenomena. 
And  this  is  intelligible  when  we  understand  that  tlie 
nerve-centres  stimulate  into  action  the  organs  the}^  inner- 
vate, but  do  not  by  themselves  play  any  other  part. 

90.  "  The  man "  then  does  not  feel  the  prick  on  his 
leg,  but  his  leg  feels  it.  The  man  has  no  consciousness 
of  what  takes  place  outside  the  sphere  of  his  sensitive 
mechanism ;  and  the  leg  is  now  outside  that  sphere. 
Consciousness  —  as  distinguished  from  Sentience  in  gen- 
eral —  we  have  seen  to  be  a  resultant  of  the  composition 
of  forces  co-ojoerating  at  the  moment ;  the  Sensibility  of 
the  spinal  cord  in  the  regions  below  the  injury  cannot 
oiovj  enter  into  that  composition.  It  is  detached  from  the 
upper  organs.  But  inasmuch  as  the  organs  it  innervates 
are  still  living  and  active,  the  functions  of  this  detached 
jjortion  are  still  displayed.  We  have  seen  the  dog  with 
divided  cord  capable  of  Urination,  Defecation,  Generation, 
etc. ;  its  hinder  legs,  though  not  moving  in  a  consensus 
with  the  forelegs,  yet  moved  independently ;  and  all  the 
normal  reflexes  of  the  parts  followed  on  stimulations. 
To  say  that  "the  dog"  showed  no  signs  of  Sensibility 
when  its  hinder  limbs  were  irritated,  is  identifying  "  the 
doGC "  with  the  anterior  half  of  the  oroanism  which  was 
not  in  connection  with  the  posterior  half.  It  is  equally 
true  that  the  posterior  half  showed  no  signs  of  Sensibility 
when  the  anterior  was  irritated.  The  two  halves  were 
united  by  the  circulation,  nutrition,  etc.,  but  disunited  as 
to  sensation  and  volition. 

91.  Do  I  then  suppose  the  separated  half  of  an  animal 
to  feel  pain  and  pleasure,  hope  and  terror  ?  The  reader 
who  has  "attentively  followed  the  exposition  will  be  at  no 
loss  to  answer.  Pain,  pleasure,  hope,  and  terror,  are 
special  modes  of  Sensibility,  dependent  on  particular 
neural  combinations.  The  organs  comprised  in  the  an- 
terior half  of  the  animal  furnish  the  main  conditions  for 
these  special  modes,  whereas  the  organs  comprised  in  the 


THE   KEFLEX   THEORY.  -555 

posterior  half  furnish  few  or  none  of  those  —  they  con- 
tain none  of  the  special  Senses,  and  they  are  without  the 
chief  combining  centre,  the  brain.  But  since  we  know 
that  a  large  amount  of  normal  Sensation  is  wholly  with- 
out the  special  characters  of  pain,  pleasure,  hope,  or  terror, 
we  need  not  hesitate  to  assign  Sensation  to  the  spinal 
cord  because  these  characters  are  absent. 

92.  All  I  contend  for  is  that  tlie  spinal  centres  have 
Sensibility  of  the  same  order  as  the  cerebral  centres  ;  and 
that  in  the  normal  organism  this  Sensibility  enters  as  a 
factor  into  the  general  Consciousness  —  no  one  portion 
of  the  nervous  system  being  really  independent  of  all  tlie 
others,  all  co-operating  in  every  result.  Over  and  over 
again  I  have  had  to  insist  that  the  property  of  Sensibility 
is  only  the  general  condition  of  Sensation  ;  and  that  each 
particular  sensation  receives  its  character  from  the  organs 
innervated,  ]jIus  the  reaction  of  the  whole  organism.  Ob- 
viously, therefore,  the  peculiar  character  of  a  sensation,  or 
"state  of  consciousness,"  must  vary  with  the  variations 
in  either  of  these  factors.  To  say  that  every  segment  of 
the  spinal  cord  has  Sensibility,  is  not  saying  that  an  ex- 
citation of  that  segment  will  produce  a  particular  sensa- 
tion of  definite  character-;  because  for  this  definite  char- 
acter there  is  needed  the  co-operation  of  all  those  parts 
of  the  mechanism  which  enter  into  the  complex  product. 

93.  And  here  attention  must  be  called  to  a  double 
fallacy  pervading  the  arguments  on  the  other  side.  It  is 
always  assumed  that  the  reactions  of  an  organ,  or  part  of 
tlie  organism,  when  separated  from  the  rest,  are  typical 
of  their  reactions  when  forming  constituents  of  the  nor- 
mal organism.  Nothing  of  the  kind.  The  movement  of 
a  muscle  or  a  limb  separated  from  the  body  may  resemble 
that  movement  when  normally  effected  —  but  only  as  the 
movements  of  a  mechanical  bird  resemble  those  of  a  liv- 
ing Ijird  :  the  modes  of  production  are  different.      So  that 


556  THE  niYsicAL  basis  of  mind. 

were  we  to  grant  the  postulate  of  the  brain  being  the  ex- 
clusive seat  of  sensation,  we  should  still  deny  that  an 
action  which  was  effected  after  removal  of  the  brain  was 
typical  of  the  action  effected  when  tlie  brain  ^vas  present. 
The  leg  of  Hunter's  patient  jerked  when  the  skin  was 
irritated ;  but  this  action  could  not  be  altogether  the 
same  as  the  similar  action  in  a  leg  united  with  the  rest 
of  the  sensitive  mechanism.  Nor  is  this  all.  The  leg 
may  have  been  insensible,  the  spinal  segment  which  in- 
nervated it  may  have  been  wholly  without  Sensibility, 
and  still  we  should  have  to  question  the  logic  Mdiich  ex- 
tended such  an  inference  to  the  very  different  and  far 
more  complex  actions  of  decapitated  animals.  On  this 
ground :  —  The  leg  is,  by  the  hypothesis,  insensible  be- 
cause cut  off  from  all  connection  with  the  sensiti^'c 
mechanism.  But  this  is  not  the  case  with  the  decapi- 
tated animal :  there  still  remain  the  essential  parts  of  a 
sensitive  mechanism  —  all  the  chief  organs  are  still  in 
activity,  still  manifesting  their  functions.  Decapitation 
has  produced  a  great  disturbance  in  the  mechanism,  and 
has  removed  an  important  centre ;  but  nevertheless  every 
impression  excites  a  connected  group  of  centres,  and  this 
group  responds. 

94.  In  conclusion,  unless  we  adopt  the  opinion  that 
Sensation  —  Consciousness  —  Sensibility,  is  something 
not  belonging  to  the  physiological  properties  of  the  ner- 
vous system  in  a  vital  organism  ( the  opinion  held  by 
spiritualists  ),  there  seems  no  alternative  but  to  adopt  the 
opinion  advocated  in  this  volume,  namely,  that  the  phys- 
iological properties  of  the  nervous  system  are  inseparable 
from  every  segment  of  that  system ;  and  the  functions 
are  the  manifestation  of  those  properties  as  determined 
by  the  special  organs  with  the  co-operation  of  all. 


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